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Drainage among keys to growing coneflowers
By Kathy Huber | September 7, 2012
Q: I have been trying for years to grow purple coneflowers. The ones I bought in early spring have black leaves and no flowers.
A: I've found purple coneflowers are best in full sun, good air circulation and an organically enriched, well-draining soil. Although established plants are touted as drought-tolerant, a moist soil during the growing season makes for better-looking plants. Avoid wet soil and overhead watering as they can encourage disease.
Dark lesions and wilting are symptoms of Sclerotinia blight. Remove infected plants and avoid planting another coneflower in the area. Botrytis is a fungal disease that is not necessarily fatal but causes ugly gray-brown mold on plant parts. Remove diseased flowers and foliage and practice good culture.
Several cultivars are available, and some grow much better than others in this area. 'PowWow Wildberry,' 'Magnus' and 'Rubenstein' are among the best performers. You may have better luck growing native Echinacea purpurea from seed.
Q: What can be used to help control the weeds in an elementary school garden? We can't use herbicides.
A: Pull the weeds by hand, then place a 2- to 3-inch layer of organic mulch to discourage new weeds. Some people cover layers of newspaper with shredded bark mulch or pine needles for a neater appearance.
Q: Can I root a fallen plumeria branch, and if so, how?
A: Plumeria Society of America member Eulas Stafford has this advice: Remove all the leaves. Plant the branch in a container of good potting soil, and stake it to keep it upright. Water well, and place the pot on a sidewalk or other warm surface. You can mist the top, but don't water the soil. Once new leaves emerge, water and fertilize lightly.
Q: My loropetalums have grown leggy spikes this summer. Is it too early or hot to prune these plants?
A: You can trim to shape the plants. Water slowly and deeply if the soil is dry. Prune more heavily after early spring blooms.
Q: We have a Mexican olive tree loaded with fruit. Are the olives edible? I've heard yes and no.
A: On its website, the Texas A&M Forest Service lists the fruit as edible but recommend using it to make jelly. Several sources say eating several fruits at once may cause dizziness.
Mexican or Texas wild olive (Cordia boissieri) is a drought-tolerant small tree with spring-summer, trumpet-shaped white flowers with yellow throats and fuzzy leaves. Wildlife loves the fruit.