- My pampas grass didn’t bloom last year and looks like it’s dying. It’s never been pruned or divided. What can I do and when?
Cortaderia selloama is native to Brazil, Chile and Argentina, hence its common name pampas grass. It is hardy to zones 8 to 10. Given last winter’s extreme cold for a few days, -21C, it could have perished from being too frozen to recover. Another reason for it to look like it’s dying is that, unless pruned and divided, the centre of the clump can die and rot causing the plant to fail. We have had dry summers so lack of water during the dry season could also have caused it to start dying. Pampas grass has a lifespan of around 10 to 15 years unless divided.
The grass should be cut back in spring before new shoots are showing. Use hand tools or a power hedge trimmer as the grass blades are very sharp. You can trim down some of the growth now but not too close to the ground and put a pile of leaves over top of it for winter mulch. In the spring dig out clumps around the edges of the centre and replant with some well rotted compost mixed in. New shoots may grow from the original clump. If no shoots appear by late spring the whole plant may have died. Pampas grass are late bloomers and the plumes appear later in the summer and last into fall. If the newly divided clump starts growing, keep it adequately watered in dry periods. Plant away from flammable structures as the leaves and plumes are flammable in dry weather. Cut the plant down in early spring and add some compost to the soil around it. Mulch in fall with leaves to protect it from cold temperatures. Pampas grass is a semi tropical grass species so it is prone to damage in colder than normal temperatures in winter.
Sources:
https://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=285194 https://www.thespruce.com/how-to-grow-pampas-grass-5194991
Brickell, C. & Joyce, D. (Eds), (2017). Bamboos, Grasses, and Herbaceous Perennials in Pruning and Training What, when and how to prune (pp 166-167). DK Publishing.
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