You Asked Us – August 2026

Q. How hard can you prune Rosemary?

Rosmarinus officinalis, commonly known as Rosemary, is a shrub with fragrant, evergreen needle-like leaves and purple or sometimes white, pink, or blue flowers. It is a member of the mint family, Lamiaceae. and native to the Mediterranean region. It has numerous cultivars and its leaves are commonly used as flavouring.

The plant has a fibrous root system and flowers in spring and summer in temperate regions but may be in constant bloom in warm climates. The branches are dotted with groups of 2 to 3 flowers down their length. Rosemary also tends to flower outside its normal flowering season; it has been known to flower as late as early December and as early as mid-February in the Northern Hemisphere. The plant can live as long as 35 years. It is very easy to grow and needs little maintenance once established. Since it is attractive and drought-tolerant, Rosemary is used not only as a culinary herb but also as an ornamental plant in gardens and for xeriscape landscaping. It is considered easy to grow and pest-resistant and can grow quite large, retaining attractiveness for many years. It prefers a site in full sun with light, free-draining soil. Rosemary hates having wet roots, especially in winter.

Rosemary is evergreen, so can be harvested all year round, but the soft new growth in late spring and summer has the best flavour. Snip off shoots as required, aiming to keep an attractive shape to the plant. The leaves can be used fresh or dried for later use. To dry rosemary, hang up sprigs in a warm, dark, well-ventilated place. When fully dried, strip off the leaves and store in an air-tight jar.

To keep rosemary compact and encourage fresh young foliage, trim it back lightly every year after the flowers fade, but avoid cutting back into old wood. Varieties with an upright habit can be grown as a neat hedge if trimmed annually. Left unpruned, rosemary will become leggy, woody and bare at the base. As they don’t usually recover from heavy pruning, old straggly plants with a lot of bare, woody stems are best replaced. You can purchase new plants from a reputable nursery or garden centre but it is also easy to take cuttings from a plant that needs to be replaced and create free new plants which will be clones of the original.

Cuttings can be of two types:

1) Softwood cuttings have the highest rooting potential of any stem cutting and often provide the best chance of rooting. The cuttings are taken in spring and early summer, from the tender new growth of the season.

Collect material early in the day when it is full of water (turgid).

Collect non-flowering shoots, as they will root more readily.

Remove up to 10cm (4in) of shoot, cutting off the material neatly above a bud on the parent plant.

Place the cuttings material in a clean plastic bag. Store the bag of material in the fridge if you cannot prepare the cuttings immediately.

Remove the lower leaves and pinch out the soft tip. Poke holes at least an inch or two (3-5 cm) deep around the outer edge of a container of peat-free compost or potting soil mixed with a little sand. Plant the cuttings up to the first set of leaves, firming the soil gently around them then water from above to settle the compost. Ensure the soil remains moist but not soggy.

Place the pot in a closed plastic bag in a warm location but not in direct sunlight.

Open the bag for a few minutes every few days to ventilate.

The cuttings should root in 4 – 6 weeks.

2) Hard wood cuttings are taken in the fall in much the same way as softwood cuttings. Select a 4 -6’ piece that is hardwood at the bottom but with a soft tip. Remove all but the top few leaves and continue as per softwood cuttings. You can also take a ‘heel cutting’ by pulling a shoot downwards and taking a ‘heel’ of stem with it.

The amount of old woody growth on your Rosemary bush will determine whether it can be pruned or whether you should replace it.

Sources

https://www.rhs.org.uk/herbs/rosemary/grow-your-own

https://en.wikipedia.org/wiki/Rosemary

Photo: By Margalob – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=47807064

My own herb garden

Q. How do I get rid of Lesser celandine that has completely covered my son’s back garden? My grandchildren play outside there all the time.

https://www.flickr.com/photos/tanaka_juuyoh/7028176673

Ficaria verna, (previously Ranunculus ficaria) commonly known as lesser celandine, fig buttercup or pilewort, is a low-growing, hairless perennial flowering plant in the buttercup family Ranunculaceae. It has fleshy dark green, heart-shaped leaves and distinctive flowers with bright yellow, glossy petals. Lesser celandine is native to Europe, northern Africa, western Asia, and Siberia. It is believed to have been first introduced to North America as an ornamental in the mid-1800s and escapes were reported in Pennsylvania in 1867. Dense colonies were originally associated with moist soils near streams or around spring seeps. Lesser celandine continues to be found in those locations; however, lush aggregations are now commonly found blanketing well-drained gardens, woodlands, hillsides and hilltops.

It is a “spring ephemeral” meaning it spends most of the year hidden from view underground. The plant’s shoots typically emerge as early as late January to February with flowers beginning to bloom in March and April. By June, the vegetation has died back and the plant becomes dormant as trees fully leaf out. The plant’s hide-and-seek life cycle makes detecting and evaluating the extent of spread a time-sensitive endeavor. The roots are tuberous, and detachable bulblets (small bulb- or tuber-like reproductive structures) can also form where the leaves join the stem. It is very short ground cover about 3 to 9 inches tall and about 1 foot wide. The plants form a carpet of foliage with no above-ground growth present during dormancy. The glossy yellow daisy-shaped flowers are bright yellow with eight to 12 petals and stalks long enough to hold them above the foliage. The base of the petals surrounding the flower center are darker, looking as if they were water-soaked. The leaves are simple (not divided into leaflets), kidney shaped with slightly lobed or angular margins and smooth with a waxy texture. They are arranged alternately on the stems, though the plant is so compact this trait is hard to see.

This invasive plant creates a dense carpet of vegetation that smothers other species. It is also toxic to most mammals causing sickness in livestock and rare deaths. Its ability to reproduce in two ways both vegetatively by means of bulblets that scatter as the foliage dies back, plus seed from pollinated flowers, make it an aggressive spreader. Lesser celandine can be managed without the use of herbicide, but the process takes more effort and time and may not always be fully effective. After the plants go dormant, the only way to remove them is by screening the bulblets and tubers out of the soil manually. Due to their small size and variable depth, and the requisite soil disturbance, this is not practical where lesser celandine has invaded lawns, garden beds, or wooded areas. The successful removal of established lesser celandine colonies may take many years of pulling or digging the plants out of the ground during the brief period of time they are actively growing. This can be a good opportunity for a ‘weed pulling party’ with friends and neighbours as the celandine can easily spread to neighbouring properties. Lesser celandine can wreak havoc on our native plants in its short lifecycle which makes early detection and control key to protecting our native nectar sources of spring.

Smothering a patch to deprive the plants of light might weaken them if begun promptly as soon as new growth emerges in early spring, while mowing the leaves off could also help weaken the plants although they usually grow too short to be cut by a mower. A string trimmer used to selectively mow-down a patch may work. One risk of mowing is accidentally dispersing any bulblets present. Removed plant parts should be bagged and disposed of as garbage and should never be composted.

Herbicides are not recommended both because of the toxicity to humans, animals and other plants but also the very limited window of time when herbicide can be absorbed by live foliage to have any effect.