Actual questions with answers presented to Master Gardeners at clinics in our community covering a wide range of gardening topics. Some are quite unique while others more frequently posed. The following responses have been researched by members of the Victoria Master Gardener Association (VMGA). Check back on a regular basis to find new questions presented each month.
January Clinic Questions:
I would like to grow an indoor herb garden. What kinds of herbs can I grow indoors? What kinds of conditions do herbs need?
An indoor herb garden is a great way to keep your hand in gardening all year and provide you with fresh herbs at home for a fraction of the cost of buying them at the grocery store. This is a great gardening alternative for apartment or condo dwellers too. An indoor herb garden takes no more time and effort than any houseplant. With just a little planning, you can grow a luscious array of tasty treats to be added to soups and salads, and used as garnish.
The first thing to consider is the lighting available in your home. Most herbs need as much light as they can get to grow successfully. A sunny spot that that gets four to eight hours of sunlight is sufficient. Windows that face south, southwest, east or west are best though south facing windows may be too hot in the summer and require some shade. North facing windows do not get enough light for growing herbs. As the light quality drops quickly away from the window, you’ll want to place the plants fairly close to the light source. Remember to rotate your plants toward the light so all sides flourish and the plant does not lean to one side. If you do not have a window with sufficient light, you can use fluorescent grow lights, placing them just above the plants (four to six inches) and leaving the lights on for about eight hours. Full spectrum grow lights come in different sizes and prices vary.
Herbs are like people in that they prefer indoor temperatures between 18-21 degrees C. (or 65-70 degrees F.). At night, the temperature close to a window may drop to 12 C. (or 55 F.) but most herbs don’t mind as long as the leaves don’t touch the window glass (brrrr). Some herbs, like basil, do not like the cold and prefer to be warm throughout the day (about 21 C. or 70 F.). Keep your herb garden away from the drafts caused by open windows or doors.
Now, how to choose the herbs for your indoor garden. This will partially depend on your taste (literally!) and the type of lighting available. There are many herbs, leafy greens, lettuces, edible flowers and some peppers that will thrive indoors. Some plants that love and need a VERY sunny location are: thyme, oregano, sage, marjoram, chili peppers, basil, parsley, cress and calendula. Others prefer a slightly shadier spot: mint, chives, lettuce, spinach, parsley, thyme, mizuna, and miner’s lettuce. You might want to start with just two or three of your favorites (e.g. oregano, chives and mint or rosemary and thyme). If planting many different types of herbs together, you’ll want to choose ones that like similar conditions (e.g. Mediterranean herbs such as oregano, marjoram, thyme particularly love sun and good drainage; lettuces grow well together). Some herbs, like the mints, tend to take over an area and should be grown in a pot by themselves. Mint may require frequent repotting. Rosemary, bay, and sage can be left in a container for several years before repotting.
Next, you will need to select containers for your herbs. While any pot at least six inches deep will do, glazed or plastic pots do not dry out as quickly as other types of pots. The deeper the pots, the more room there is for root growth. Window boxes are ideal. Make sure the container has drainage holes and set the pot on a saucer, liner or drain pan. You can even set the pot on some pebbles in the saucer. This serves two purposes: first, it provides humidity for the herbs that may be warranted in dry indoor air, and second, it reduces the likelihood that the pot (and roots of the herbs) will be sitting in water. Herbs don’t like to get their feet wet!
You will want to use a good quality potting mix in which to grow your herbs. The nutrients in the soil will feed the plants and fertilizing will be kept to a minimum. Herbs do not require much feeding from fertilizers in the winter but occasional feeding (once per month) with a food-safe natural product may be warranted in the growing season. If you want to grow your herbs from seed, you can plant the seeds in some starter mix (lighter and airier that potting soil) in smaller containers like peat pots and transplant them into your larger herb containers when they have at least two sets of true leaves (about eight centimeters tall). Or you can purchase starter plants or seedlings from nurseries or garden centres. These are usually available from late spring until the fall. Put some soil in the bottom of your container, place the plant gently on top of the soil and fill with potting mix, pressing the soil firmly around the plant. Make sure the crown (where the roots meet the stem) is level with the top of the soil (i.e. not buried). Leave some room at the top of the pot (about one inch) to allow for watering. Try putting three plants in a window box, leaving some space between them so they have room to grow. While you’ll want to keep your herbs watered regularly, they don’t want too much water and never want to stand in it. Too much water will cause them to wilt and lose their flavour. Check them daily and water when the top of the soil feels dry. Never let them dry out completely. Remember that different plants may have different watering schedules and this may change with the seasons.
Herbs are not bothered much by pests but if you see some bugs chewing on the leaves, mix up a mild solution of soapy water and spray well.
In very little time, you will have herbs growing, though they may appear more stretched out and spindly than those grown outside and will not be quite as productive. You can still harvest the leaves regularly but never remove more than one third of the plant. This might even encourage the plant to become more compact. If you are aiming for edible flowers (e.g., violas, calendula, pansies), be sure not to remove the flower buds. You can harvest fresh herbs by pinching back the tips of the stems to eat them fresh or cut the stems and air-dry them in bunches. You can move your containers outside in the summer and bring them in again before the first frost in the fall. Remember to check for pests when you bring them in. Better yet, keep your herb garden indoors all year. Happy herbing!
Royal Horticultural Society: https://www.rhs.org.uk/advice/profile?pid=142
Montreal Botantic Garden: http://espacepourlavie.ca/en/growing-herbs-indoors
Growing Herbs by Y. Rees & R. Titterington, Whitecaps books, 1994.
What should I be doing in my garden during the winter months (Nov. – Feb.)? What can I do to get ready for spring?
Well, what you do in your garden during the winter months really depends on how active you wish to be. For those living near coastal B.C., there are a number of gardening activities that can be pursued throughout the year.
Many edible plants such as vegetables can be planted in the summer for fall and winter harvesting (i.e. winter gardening). These include arugula, broad beans, calendula, chervil, corn salad, lettuces, mescluns, mustards, pac choi, scallions and turnips to name just a few. Other plants can be kept in the ground over winter (i.e. overwintered) for harvesting in the spring and summer. These include certain varieties of garlic, onion, cauliflower and broccoli. They need this extra time to fully develop and do not require protection during the winter. In early spring, they will start to grow quickly and you can harvest them as you are planting your spring crops. You can also plant bulbs like tulips in late fall, if you have not done so already.
Another activity that can be carried out, if you have not already done so, is cleaning up and preparing your garden for spring. In the late fall, there are likely to be fallen leaves and woody debris that can be removed. This is particularly important if you have a pond with fish as the leaf decay releases methane gas into the water which can be fatal to fish. You will also want to cut back herbaceous perennials and pull out annuals or other debris to prevent rot. Many communities pick up kitchen and garden waste or have composting centres. Some communities also have composted materials available for use by area residents – check out your local municipal website. You may also wish to raise your containers onto pot feet (or little blocks of wood) to prevent water-logging.
You can also take this opportunity to prune out diseased, dying or dead branches from shrubs and trees. When no leaves are present, it is easier to see where these areas are and the plants are dormant at this time. You may also wish to remove any odd looking branches or prune to enhance the shape of the shrub or tree.
Another great later fall and winter activity is to enhance your garden soil by applying mulch to your garden. Organic mulches can contain compost (commercial or homemade), composted sawdust, chopped or composted leaves. Two to three inches of mulch can be applied but be careful to avoid the crown (where the stem meets the roots) of perennial plants, just bringing the mulch up to the edge of the crown.
You may also wish to set out slug traps by filling an empty tuna fish or cat food can with beer (even the non-alcoholic variety will attract slugs) placing it in a shady spot with the rim of the can at ground level. Empty the can every few days and refill. Be sure you are not also catching creatures that are beneficial to your garden.
Winter is also a great time to walk through your own garden or local botanical gardens to view the variety of plants with winter interest. Interest in winter may come from flowers, berries, coloured stems or foliage. Hellebores and some varieties of clematis bloom over the winter months. Other plants like mahonia and hamamelis (Witch hazel) bloom over the winter months in bright oranges or yellows. Some varieties of cornus (dogwood) have spectacular winter bark or fruit. Many shrubs like nandina have a lovely display or berries over the winter months. By January, some of the early bulbs like galanthus are beginning to bloom. There is never a dull moment in the coastal garden!
Another way to be working on your garden during the winter months is to check out seed catalogues and lists and make some choice selections for spring planting. While seed catalogues are now available to leaf through (pardon the pun), many plant lists are also available via the internet with easy access to information on each plant with direct links. How easy does that make gardening? Happy winter gardening!
Canadian Wildlife Federation: http://cwf-fcf.org/en/resources/gardening/gardening/putting-your-garden-to-bed_resource.html
Royal Horticultural Society: https://www.rhs.org.uk/advice/in-month
West Coast Seeds: https://www.westcoastseeds.com/
Canadian Gardening’s Water Garden by J. Davis, Penguin Studio, 1997.
Where is the best place to buy soil?
Before you buy soil by either picking it up yourself or having it delivered, have a good look at what you are buying. Good quality soil is called loam, and is a mix of roughly equal proportions of sand, silt, and clay. It should have good structure and be well drained. All soils benefit from the addition of organic matter such as well rotted compost.
Look out for things such as a high stone content, thick fibrous roots, weeds, and contaminants such as brick or glass. Ask the supplier where it is from and whether it has been tested and what are the results. Check for evidence of invasive plants such as Japanese knotweed, horsetail, couch grass, and weed roots and shoots. Weed roots are often white and fleshy.
Here is a list of local suppliers:
MacNutt Enterprises Tri Landscape Supply Michell Excavating Integrity Sales and Distribution Victoria Landscape Gravel Mart Peninsula Landscape Supply Gardenworks Blenkinsop location
When do you take scions for grafting?
Grafting and budding are used as the principle methods of propagating in certain plants such as fruit trees. They are techniques used to combine one plant with another to encourage growth as a unified plant, one that is identical to the parent plant.
Factors affecting successful grafting or budding are: temperature, time of year, age of the plant parts, scion orientation, and care of grafted plants, soil moisture, and contact of stock and scion.
According to Ross Penhallegon, a horticulturist with the Oregon State University Extension service, peach, nectarines, cherry, and prune wood is best collected in late January. Apple, Asian pear and pear wood should be collected in early February. Scion wood should be cut from the whip-like growth found in the tops of superior quality trees. One year old wood is preferable to older wood and should be of average vigor and well hardened. Wood grown in sunlight is better than that grown in shade. Scion wood can range from 8 to 18”, about the thickness of a pencil, and be free of insects, diseases, and frost injury. Begin grafting whenever weather conditions cause sap to rise freely, and the buds at the top of the tree to swell.
Sources: “Grafting Ornamental Plants and Fruit Trees”, Royal Horticulture Society, www.rhs.org.uk Oregon State University Extension Services, oregonstate.edu, Carol Savon, “Propagation of Plants by Grafting and Budding”, “It’s time to gather scion wood for grafting”
What is a good book about garden design?
The Victoria Master Gardener’s Association (VMGA) Landscape Design Group has some excellent resources listed on their web page. One of the most interesting (in this writer’s opinion) is the book “Plant Driven Design: Creating Gardens That Honor Plants, Place, Spirit” by Lauren and Scott Ogden. The authors write that we don’t have to know all the tenants of design to create an interesting garden. In fact, they say most of the plans taught in landscape architecture programs are formulaic and gardens end up looking like a home improvement project. The Ogdens think that by making plants, their character, structure, individuality, and seasonality the focus of the garden returns gardening to being a relationship between plants and people a happy one. They suggest beginning by observing nature, how plants grow in the wild, where they look their best with other plants. They believe gardening is about curiosity and change, that a garden that is perfect all the time is boring. We want to go out the door and see something different every week. It is human nature to want change. If everything was the same we wouldn’t see it. Unpredictability and imperfection is part of nature. Style is less important that having plants we really enjoy.
Sources: VGMA website, Landscape Design Group, “Plant Driven Design: Creating Gardens That Honor Plants, Place, Spirit” by Lauren and Scott Ogden, Timber Press, 2008
October Clinic Questions:
Can I plant an evergreen hedge in the fall and what kinds of things should I do to prepare the area.
Fall is a good time to plant as the soil is not inundated with water and it isn’t yet cold with frost making it easy to dig. Plants are going into dormancy at this time of year so by getting them in the ground now, they will be in place for their roots to grow the following spring.
Proper preparation when planting your evergreen hedge gets plants off to a good start. Decide on the species you are going to use and investigate the mature width and height and the recommended spacing. Ensure the planting site has adequate drainage and receives enough sunlight for growth requirements.
Prepare the area where the plants will be planted by digging a trench. Soak the planting holes with water and watch to see how long it takes to drain. If it doesn’t there is a problem. You can fix it by either creating a raised bed, installing a drainage pipe, installing a drainage ditch or if it isn’t severe amend with organic matter at the bottom of the dug trench.
Organically rich soil is preferable to help maintain moisture. Supplementing the existing soil with triple mix, compost and or manure will only improve the soils water retention. If you are adding bonemeal or fertilizer make sure to mix all amendments thoroughly with existing soil. Depending on the type and size of plant you have chosen, space the plants accordingly and replace soil around plants tamping down to ensure the plants don’t tip over.
Mulch is an excellent method of adding nutrients to the soil, slowly over time. It also acts as an insulator, maintaining a cool soil temperature, reducing evaporation from the soil’s surface as well as keeping weeds at bay. Ensure the plants are well watered during a dry spell. Top dress with mulch annually.
Royal Horticultural Society
Why does winter squash taste better if left on the vine till late fall?
Of course you can harvest any time they’ve reached mature size but squash develop more sweetness if left on the vine till the leaves start dying back in the fall.
Winter squash become sweeter after a hard frost or two but they should be harvested and cured if the temperature drops below -5c. Most winter squash become sweeter after a couple of months of storage and can be kept up to six months if stored properly.
Over time, in storage, some of the flesh’s complex starch (dry matter) breaks down into simple sugars and water. The 4 VMGA MEMBER PHOTOSresult is squash with improved flavour - a sweeter and pleasantly moist taste. There is an optimal storage period, which differs for each type of squash; after that the squash may appear to be storing well but usually the flavour will decline.
September Clinic Questions:
I have some gray, powdery substance in my vegetable garden (on the foliage and stems of my zucchini, squash, and pumpkins). What is this, is it harmful and what can I do about it?
Given your description of the substance and the time of year, I think your vegetables are being affected by a fungus called powdery mildew. It appears as a white or light gray powdery or furry-textured coating on plants in the late summer and fall. Old leaves are more susceptible than new growth and maintaining vigorous growth helps keep the fungus away.
There are different species of powdery mildews that attack different host plants. Members of the squash and cucumber family are particularly susceptible but other edibles can be affected too such as apples, black currants, gooseberries, grapes, rosemary, and peas. Powdery mildew can also affect ornamental plants such as delphiniums, phlox, rhododendrons, azaleas, and roses.
Powdery mildew typically affects the stems and foliage of plants but sometimes you can also see it on the fruit and flowers. The fungus is present in many places in the garden and can overwinter on plants or in plant debris. The spores of the fungus are spread by wind, rain, insects, or even on the feet of birds. When the right strain of powdery mildew finds the right host plant, the fungus rapidly attacks the surface of the leaves, taking nutrients from the leaf while forming the powdery substance on the leaf.
On vegetables, the fungus typically only affects the leaves and stems but loss of leaves can affect how many squash or cucumbers are produced. Some people recommend removing the affected leaves but others note that the spores have already spread by the time we notice the powdery substance. By not removing the leaves, the plant is likely to continue to get some benefits from photosynthesis. When the affected leaves turn brown and dry up, they can be composted. Just pick the vegetables when they are mature and wash them.
If you notice the powdery mildew early, there’s a few things to try to keep its growth in check. Powdery mildew spores cannot germinate when there is water on the leaves so you can rinse off all the leaves (on both sides) with water at mid-day so the leaves have time to dry before nightfall. Do this several times per week. Another idea was discovered by Canadian researchers: a mixture of milk (e.g., skim, 2%, whole) and water. Different people recommend different ratios of milk to water in the mixture: 10% milk to 90% water, 30% milk to 70% water, or 40% milk to 60% water, always using more water than milk. The proteins in the milk interact with the sun to create an antiseptic effect. To be most effective, the milk mixture can be used preventatively by applying it in bright light every 10 days or so.
Prevention is key with powdery mildew – try to water the morning, rather than the evening, to allow plenty of time for leaves to dry during the day and choose mildew resistant or tolerant cultivars. Check seed catalogues for powdery mildew resistant zucchinis, cucumbers, grapes, and other plants.
Royal Horticultural Societyhttps://www.rhs.org.uk/advice/profile?pid=253
Master Gardeners Association of BC: http://mgabc.org/content/powdery-mildew-aphid-infestations-early-mid-fall
Sunset Western Garden Bookedited by Kathleen Norris Brenzel, p. 666
Natural insect, weed and disease controlby Linda Gilkeson, page 147-148
I planted a single hosta in my garden about five years ago and now I have a clump growing. Is this OK? Can I divide them and plant some in other parts of my garden or share them with friends?
Hostas are known to be a wonderful foliage plant for shady locations that are easy to grow. They come in a variety of sizes (from miniature to huge!) and colours (e.g., light to dark green to chartreuse to gray and blue). Colour combinations may include white, cream or yellow borders or stripes. The leaf textures vary from smooth to quilted to puckery. The flowers can also be lovely and many are fragrant.
Hostas grow best in good, organically enriched soil with regular feeding during the growing season. Hostas require moisture to thrive and must not dry out for long periods. Clumps expand in size over the years and can remain vigorous without division. Hostas also do well in containers. You can divide a hosta clump to move pieces to another location in your garden or to share it with your luckiest friends or neighbours.
Hostas can be divided in the fall or spring, although late August may be the best time to divide hostas. If doing it in the fall, be sure to do it early enough so that the roots are established before any chance of freezing weather (6-8 weeks before a hard frost). A day or two before you are going to divide the plant, moisten the soil around the clump. On the day of dividing, follow the steps below. Be sure to have the new bed prepared for the division and if you plan to share, have a pot(s) with fresh soil that you can pop the division(s) into so roots remain moist and protected until they arrive at their new home(s).
Steps to divide a hosta:
- Lift the clump with a pitch fork being careful not to damage the growing points
- Place the clump on board or plastic sheet
- With a sharp spade or old kitchen knife, cut between the shoots so you have 4-5 shoots per clump or sections can be prised apart with two pitchforks
- Replant sections in the ground at the same depth they were before you lifted the clump, with shoots poking through the soil surface
- Water the freshly planted plant sections (in ground or pots)
Sunset Western Garden Bookedited by Kathleen Norris Brenzel, p. 391 and 700
American Hosta Societyhttp://www.americanhostasociety.org/Education/hosta_gardening_calendar.htm
August Clinic Questions:
What Should I Do With My Raspberries This Month?
Well that depends on whether you have canes that fruit in the summer or late autumn.
Most hybrid cane fruits (including blackberries) operate on a biennial system with the canes growing during the first year and then flowering and fruiting during their second summer. Once the fruit is picked, cut down the canes to just above the ground; this will make room for new shoots.
If you have late autumn bearing canes, cut them down to just above the ground in early spring before new growth starts.
With both types, after pruning, apply a 2-3" layer of compost or aged manure and water thoroughly.
Is There Any Pruning In My Ornamental Garden I Should Be Doing Now?
Yes, August is a great time to prune some of your woody ornamental trees. Sap bleeding will be at its lowest during the day when the evaporation of water from the leaves will not only reduce the pressure in the zylem (water conducting tube) but will actually create a strong tension in the system, therefore reducing bleeding.
Ornamental trees such as Japanese maples, Beech, Birch, Oak, American Ash, Maples, all take pruning well this time of year.
Remember to clean your tools between trees and even between cuts on the same tree if disease is present. Lysol Brand disposable wipes work great for this.
Here's a helpful clean up hint if you find you get some pitch/resin on yourself while rattling around the garden. If you've got pitch in your hair, slather on some mayonnaise, leave for 15 minutes and comb out slowly; then shampoo. If you have some on your skin, hand sanitizer works wonders!
Source: The Complete Book of Pruning Coombs, Blackburne-Maze, Cracknell & Bentley. Cassell Paperbacks
July Clinic Questions:
How do I get rid of moss in my lawn?
This is a question we hear a lot at the VMGA and there’s a few different ways to tackle this issue.
First, it’s important to recognize that the underlying conditions favouring the moss need to be corrected otherwise whatever you do will be short term.
Here’s some ideas to get started:
- improve perimeter drainage
- apply lime to reduce the acidity in either the spring or fall
- aerate the soil and add a dressing of sand to improve drainage
- water properly – let grass rest during the summer if it’s established (more than two years old) and water deeply just once a month . Frequent sprinkling leads to shallow roots
- mow properly – remove about one third of the blade and mow in a different pattern each time to avoid soil compaction
- remember to leave the clippings on the grass after mowing for a free source of nitrogen
Another option is to replace your lawn entirely with something completely different. Given this summer’s drought and the prospect that climate change will likely lead to more of the same, consider this; conventional turf grass lawns typically consume vast amounts of precious water, are monocultures so frequently encounter problems, do not offer wildlife any refuge, often are a major source of fertilizer and chemical runoff into the environment and finally, they require a lot of work to maintain.
Did you know the average gardener spends up to 100 hours mowing every year?
Instead you could create a garden using native species that after just one year won’t need any watering at all.
Here’s just a few native species to consider, from groundcovers to shrubs to perennials
- Kinnikinnick (Arctostaphylos uva-ursi)
- Salal (Gaultheria shallon)
- Western Red Columbine (Aquilegia Formosa)
- Evergreen Huckleberry (Vaccinium ovatum)
Alternatively, you can learn to love the moss, which is soft, green and never needs mowing!
A few excellent resources to help get started include Native Plant Society (www.npsbc.org)
Naturescape British Columbia(www.naturescapebc.ca)
Make the neighbourhood a better place(Start something in your backyard): A resident’s guide to natural yard care for the Lower Mainland (pdf available online and relevant to all southern BC residents)
How to get your LAWN OFF GRASS: A North American Guide to Turning Off The Water Tap and Going Native by Carole Rubin (published in BC, 2002, Harbour Publishing)
When should I start thinking about planting winter veggies and what works best on our coast?
Despite the beautiful mid-summer sunshine, now is the time to start planning and planting your winter veggies.
According to Helen Chestnut, in the Times Colonist’s Garden Notes, early August is the “ideal time to seed autumn and winter green and salad vegetables such as spinach, radish, corn salad, mustards, mesclun mixes, leaf lettuce and cold hardy lettuces.” She also advises us to check out our local nurseries for “lettuce, kale, cabbage, cauliflower and broccoli transplants for fall, winter and early-spring harvesting.”
Sometimes it’s challenging to know when exactly to seed or use transplants, as well as what kind of protection to prepare for those cold winter months and when to expect to harvest outside of summer months. An excellent resource that includes a planting chart as well as details regarding cold hardy cultivars (e.g. two kinds of romaine lettuce, Winter Density and Rouge d’Hiver are generally cold tolerant) is the West Coast Seeds catalogue. Find one at your local garden centre or go online.
Finally, a fantastic resource for veggie gardeners is Linda Gilkeson, who lives on Saltspring Island and offers a wide variety of workshops in Victoria and beyond. A major proponent of gardening year round, her Year-Around Harvest: Winter Gardening on the Coast, details the benefits of winter gardening (fresh veggies when the cost of produce increases instore), what to grow and when, pest management information, planting plans and much more. Check out Linda Gilkeson’s websitewww.lindagilkeson.ca to order a book or check her workshop schedule.
So now it’s even easier to enjoy eating your own veggies year round without a greenhouse and be the envy of all those who know you!
June Clinic Question:
I’ve got Black Spot on my roses (I think). What can I do about it?
Blackspot, Diplocarpon rosae, is a fungal disease that appears on leaves contributing to overall loss of plant vigor. This disease appears as dark purple/black lesions on both the upper and lower sides of leaves. The fungus moves upwards from leaf to leaf, turning leaves yellow (often but not always) and may eventually defoliate the entire plant. The fungus may live on the ground or in the young stems and buds over the winter.
The fungal spores are spread by moist conditions, such as splashing water and once on the leaves, spread rapidly, ever upwards.
Fortunately, the rose-grower has a number of preventative options:
- Close in vigilance: Regular check ups of your roses will hopefully nip the problem in the bud! :) Inspect your roses often, check for healthy leaves, and remove any that are diseased. Do not compost infected material.
- Sanitation/Hygiene: The fungus lives in leaves on the ground, keep the area tidy of fallen leaves and debris, even during winter.
- Watering: Avoid wetting the foliage, water at ground/soil level. Too much water increases air humidity, a condition the fungus likes!
- Air Circulation and Sunlight: Provide space for air to move and to prevent the fungus moving from rose to rose. Sunlight helps to dry out the dew.
- Pruning: Remove weak, diseased, dead canes. Also prune for internal air circulation. In severe cases, the black spot is visible on the canes, prune back below an area of stem lesions.
- Resistant Varieties: Choose varieties resistant to black spot, however, there is no guarantee the variety will continue to be resistant. The Royal Horticultural Society suggests the older species are less affected overall.
Organic Spray: To change the pH level on the leaves, mix a foliar spray of 1tsp baking soda to a liter of water and 1 tsp of dish soap (non-bleaching) on both sides of the leaves. The soap helps to keep the baking soda mixture on the leaf. Repeat weekly and after rain.
Disposal: This is a determined fungus. We suggest you dispose of diseased leaves and canes in the garbage, or by burning. Do not introduce into the garden compost or add to the municipal collection sites.
Royal Horticultural Society, Rose black spot https://www.rhs.org.uk/advice/profile?PID=270
Missouri Botanical Garden, Black Spot of the Rose http://www.missouribotanicalgarden.org/gardens-gardening/your-garden/help-for-the-home-gardener/advice-tips-resources/pests-and-problems/diseases/fungal-spots/black-spot.aspx
May Clinic Questions:
What is an organic food I can feed my roses that will encourage beautiful blooms?
Roses are heavy feeders and food does encourage beautiful blooms. In addition, roses benefit from ongoing organic inputs and pre-bloom care.
Soil and Mulch: Feed and care for the soil!! Well draining organic, non-compacted soil to allow roots to spread and foster uptake of nutrients and water. A layer of organic mulch keeps the soil cooler, roots happier and reduces competition from weeds. As the mulch breaks down the roses will have a further supply of nutrients.
Fertilizer: Keep the proportions of nitrogen, phosphorous and potassium in the single digits. Higher ratios are not better. Start in the spring with a well-balanced, slow release fertilizer. Many rose growers use a granular, organic product. Apply a new layer of compost. Throughout the rest of the growing season apply monthly an organic liquid fertilizer such as fish/kelp or alfalfa/manure tea. Water well before applying liquids.
Many gardeners have used banana peels, chopped up and spread around the plant.
Other Considerations: Other aspects of care to encourage blooming include site selection, pruning to select strong, disease free canes, watering below foliage to discourage mildew and fungus.
Good Earth R.O.S.E. Care Monthly Guide (the organic side of the American Rose Society) http://www.organicrosecare.org/articles/calendar_socal.php
Spring Valley Roses Step by step Guide http://www.springvalleyroses.com/inthegarden/fertilizing.html
American Rose Society includes suggestions to compliment different styles of gardening from the casual to the exhibitor. http://www.rose.org/rose-care-articles/fertilizers-when-and-how/
Doug Hamby, Fernbank Science Center Atlanta , Georgia. Video: http://video.about.com/flowers/5-Tips-for-Growing-Bigger-Rose-Blooms.htm
What can I feed my tomatoes?
Tomatoes are a popular, edible annual requiring lots of sunlight, enough water and good nutrition. Grown in the ground or a container, tomatoes may grow in many different types of soil but like neutral Ph and soil amended with organic matter at planting time. Great soil gives the plants a good start but may not provide sufficient nutrients for the growing season.
According the University of Missouri Extension Site, too much nitrogen encourages leaves and green growth rather than fruiting. Thus a fertilizer low in nitrogen, high in phosphorus and with a medium to high amount of potassium. Secondary and micronutrients can be delivered through organic matter. The site recommends a first application of fertilizer when the plants are 1/3 grown, and a second two weeks after the first tomatoes are picked and the third a month later. The ratio of NPK is 10-10-10. Throughout the growing season add mulch to control moisture loss, weeds and prevent water from splashing plants.
The Canadian Gardener website recommends fertilizing twice monthly, using a water-soluble fertilizer (NPK 15-15-30). Here the amount of nitrogen and phosphorous is lower while potassium is higher.
Tomato Dirt is another site with interesting tomato information and a list of organic sources.
University of Missouri Extension fact sheet http://extension.missouri.edu/p/G6461
Ed Hulme Seeds, suggests we may over-fertilize https://www.humeseeds.com/sumtom.htm
April Clinic Questions:
What can I plant under a Walnut tree?
Planting under a Black Walnut tree (Juglans nigra) can indeed be a major challenge – according to Canadian Gardener magazine. This is because the roots, leaves, husks and buds produce a substance called juglone, which can be toxic to many plants. The poisonous zone is large too – extending 20 to 30 metres from the trunk – so it’s important to try to clean up tree debris (do not compost) and add organic materials. Some plants that are juglone tolerant and are worth trying include Virginia Creeper, Japanese Maple and European Wild Ginger. Check out this article in Canadian Gardener for more planting ideas: http://www.canadiangardening.com/plants/trees-and-shrubs/what-will-grow-under-a-black-walnut/a/29797
What can I plant under a Conifer?
A walk in the woods is in order! Typically the growing conditions underneath Conifers are considered challenging, often dry and shady to boot. However, a keen gardener can turn this challenge into an advantage simply by considering native plants. As the authors of “The New Twelve Month Gardener” so aptly write, “A walk in the woods will teach you a great deal about texture, colour and natural layering.”
Some planting ideas could include shrubs such as Huckleberry, Snowberry bush, Oregon Grape, Red Flowering Currant (a favourite of hummingbirds) or Salal. Perennials to try include ferns, foxgloves, bleeding hearts or gentians and bulbs such as camas, wild tiger lily and dog-tooth violet. Non-natives like Hardy Geraniums and Epimediums will also thrive in dry shade.
Check out some of the lovely native plant gardens nearby for inspiration – the Horticulture Centre of the Pacific, Government House and Swan Lake Nature Sanctuary.
What soil is best for flowering container garden?
This question can illicit all sorts of “animated discussion” among keen gardeners – many have their very own tried and true formula for container soils that they swear is the best of the best. Trying to keep everyone happy, I’ve turned to my trusty steed The Container Expert, by Dr. D. G. Hessayon for advice.
Clearly, as containers provide a small growing space, top quality growing mediums are important. Dr. Hessayon says that ordinary soil from the garden won’t do the trick, because it will compact, depriving plant roots of the air and moisture they need. Commercial planter soil mixes provide the right balance between good drainage and water retention.
Look for bags of either soil-based or soilless compost. The first type is best for permanent planting, as it’s heavier and holds nutrients better. For hanging baskets look for soilless compost , which is light and clean but is hard to rewet if it dries out too much. Options here include peat-based and coir-based - I think it’s important to note that peat is not an environmentally sustainable choice, so I always buy coir, a product that was previously thrown away from coconut husks and is the favourite choice of the Eden Project in Cornwall, England.
You will have to provide nutrients to your container plants. Many commercial soil mixes already contain granular fertilizer. Check labels for time limits, then provide your own fertilizer in either slow release pellet form or liquid fertilizer.
When is it safe to plant vegetables outside? What are the growth requirements?
This is a tricky question as there’s no hard and fast rule for all vegetables. For example, broad beans can be sown in February, and even in October and November (although I’ve had no luck with such early sowing) for a crop about three months later – six months for fall plantings.
Tomatoes, on the other hand, in a typical year in our area, can be successfully transplanted in late May or early June when the nighttime temperatures are reliably 10 degrees Celsius or higher.
And some vegetable continue on through the winter!
The same goes for growth requirements – each veggie has its own needs and wants for tip top production.
West Coast Seeds has a marvellous catalogue and website that clearly details timing and growing conditions for many, many vegetables from artichokes to turnips. There’s even an online Planting Chart available for download at www.westcoastseeds.com This is an excellent starting place for new vegetable gardeners.
February Clinic Questions:
What are the different kinds of garlic?
There are two main groups of garlic for the home gardener to enjoy. These are the Hardneck group and the Softneck group. In our BC climate, Hardneck garlic tends to be more reliable. Hardneck varieties such as Red Russian, Wengers Russian and Gourmet Red also supply savvy cooks with garlic scapes! (Cut off the tall flower stem that grows up and out of the bulb as they curl over, to prevent energy from going to seed production instead of the bulb itself.) Scapes can be stir fried or steamed.
Late October-November is the best time for you to plant garlic and it can be harvested in July. A reliable way to tell if your garlic is ready is to watch the leaves wither and yellow to about 2/3. Hang in a cool dry area until the skins appear papery and white; the bulbs can be stored for 4-6 months.
Garlic can be easily grown in containers as long as they are well draining, non frost-cracking and can be kept moist from planting to harvest time.
Garlic is a great companion plant in your ornamental or edible garden too; it is a natural organic repellent for aphids and spider mites!
Sources: Encyclopedia of Natural Insect and Disease Conrol, Rodale @ 1984 , A Year on the Garden Path, C. Herriot @ 2005
Can I start seeds now?
There are several seeds that you can start indoors in February in Coastal BC. Bottom heat and full spectrum fluorescent lights will help ensure success. Most seeds germinate most reliably at a soil temperature of 20-25C. Covering the seed trays with plastic and having bottom heating mats or heating coils are effective and low cost both in energy terms and purchase price. Bright light is often crucial for both germination as well as plant growth, thus, sow the seeds thinly and lightly with just a thin layer( a good rule of thumb is twice as deep as the size of the seed) of sterile potting mix over top the seeds. Consistent, soft watering is also important. A brass water mister on the end of your hose is a good tool to use at this stage of plant development.
Some edible seeds you can start now include: artichoke, leeks and asparagus. Some herbs to start now include slower germinators such as lavender, rosemary, oregano and bergamot. In addition, you can get a head start on your ornamental flower garden by starting annuals and perennials such as marigolds, viola and columbines. Of course, there are many more plants you can start now and a good planting chart can be found on the West Coast Seed website at the following link:
Source: West Coast Seed Guide 2005, 2014
November Clinic Questions:
Can I grow tomatoes in Victoria during the winter months?
Tomatoes require a certain number of growing degree-days in order to bloom, set (assuming pollination) and ripen plus sufficient hours of light. Tomatoes need warmth: warm days in the 15-17 C range and night temperatures above 10 C (the base temperature is 10 C meaning tomatoes will not grow below 10 C). At least 8 hours of sunlight, ideally in full sun. It would be possible to provide these conditions in a heated greenhouse, but would be expensive to maintain.
Source: Colorado State University Extension athttp://www.ext.colostate.edu/mg/Gardennotes/717.html
What part of the Dahlia did the Aztec’s eat?
Distinct from the fancy Dahlia of our gardens, the Aztec diet included the indigenous Dahlia pinnata found in the mountains of southern Mexico. This dahlia plant is very tall, up to 20 feet, tree-like and was known as acocotli or “water cane” according to the 1570 account of physician Francisco Hernandez. The tubers were eaten and the stems used as a water source when travelling. The Dahlia is the national flower of Mexico.
Sources: Stanford Dahlia Project and the Victoria Horticultural Society
What can I plant in my fall container? I have an evergreen perennial already – what else do I need?
A garden in a freeze proof pot! Remember the basic design principals: Colour, Shape, Texture, Form, Line and Scale. Choose combinations pleasing to the eye, proportionate to the surrounding landscape. More contrast means greater drama! Being a mini-garden, selection is crucial to health and growth plus size and site of your container.
Ensure that each plant will work with available container space, anticipated moisture levels, hardiness, sun/light and soil conditions for your container’s site and seasonal weather changes. Growth rate and mature plant size are also important considerations.
Use the evergreen perennial you already have and combine it with two or more of these year round interest evergreen plant possibilities:
- Carex (Sedges)
- Dwarf conifers – a wide variety of fir, pine, cypress, yew and spruce
- Autumn Fern - Dryopteris erythrosora
- Sword Fern - Polystichum munitum
- Holly Fern - Polystichum makinoi
- Hart's-Tongue Fern - Asplenium scolopendrium
- Deer Fern - Blechnum spicant
- Heuchera - many to choose from
- Hebes - hardier varieties
- Rhododendrons - dwarf/compact varieties
- Saracocca (sweet box)- great for by the doorway
- Skimmia - dwarf/compact varieties
Your possibilities are endless.
A few other tips to keep in mind
- plant in multiples of 3, 5, 7 ...... odd numbers are pleasing to the eye
- don’t be afraid to overplant
- container plantings lose at least one zone in hardiness (versus being planted in the ground), and more for elevations (higher floor balcony/terrace)
- use a potting soil mix that will allow for good drainage
- don’t panic, if your plants eventually get too large for your container, it’s easy to relocate them in your garden or give themaway.
Enjoy your new container!
Sources: The Pacific Northwest Gardeners Book of Lists, Ray and Jan McNeilan, 1997; Container Gardening, Fine Gardening vol. 7, 2010, Perfect Plant Perfect Place, Roy Lancaster, 2002 and Great Plant Picks www.greatplantpicks.org