May/June 2000

Gardeners Information Service

The lower branches of my Cornus stolonifera 'Silver and Gold' have rooted along the ground in my garden. Can I separate these rooted branches from the main shrub and plant them elsewhere? -M. C., Pinkerington, Ohio

The process you describe-known as layering-is indeed an excellent way to propagate your dogwood, as well as many other woody plants that have low, flexible branches, such as azaleas, Kerria japonica, and witch hazels (Hamamelis spp.). Wait until you observe new growth from the stem beyond the rooted area, then cut the branch at the node closest to the rooted section between it and the mother plant. Pinching the new growth will help promote bushiness in the new plant. When it has had time-at least one or two full growing seasons-to develop a strong root system, you can pot up the new plant or move it to a permanent location. For most plants, spring is the best time to do this. You can facilitate the layering process by bending a supple stem over and burying a short section in a shallow hole. Make sure the soil covers a node, because the tissue around the node is more likely to develop roots. It helps to make a shallow cut or "wound" on the underside of the portion of stem to be buried; applying a rooting hormone in this area can also be beneficial. Secure the buried section to the ground with wire staples or an anchoring rock and keep it well watered.

Low Yielding Rhubarb 

This spring my rhubarb plants sent up loads of flower stalks (which I cut off), but they produced few edible stalks. Are they too crowded? -C. S., Herndon, Virginia

Rhubarb is relatively slow to establish. Normally, one can harvest a few stalks the second year from a root-propagated plant and as many as desired from the third year on. Plants propagated from seeds will take an extra year. It is important to leave plenty of leaf stalks the second year to provide nutrients to the developing roots. Always remove flower stalks. Assuming you have mature plants, they may be overcrowded if they are planted closer than three to four feet apart. If this is the case, simply move some of the plants. Rhubarb requires full sun and a rich, well-drained loamy soil. It should be planted in a deep hole with plenty of compost or dried manure worked into the soil. Top-dressing with dried manure during the summer or fall of each year will usually improve the plant's performance. 

William May, Gardeners Information Service, and Marianne Polito, Gardeners Information Service Manager

Too much shade Help! 

I have two enormous, 90-year-old cedar trees. While I love the trees, finding something that can tolerate the dry, shady conditions beneath them has been a challenge. I am looking for a ground cover to line the walkways and surround the trees. I can't live with the death of another astilbe or hosta. -T.S., Seattle, Washington

Reply from AHS member Gene Bush, owner of Munchkin Nursery in Depauw, Indiana: 

Is there any possibility of limbing up the trees from the base to let in more light? Since these are mature trees, they will suck all the moisture up, but there are plants you can grow there. Instead of a single ground cover, I would try mixing several-you'll get a better survival rate and, in my view, a better display. The trick is to not let anything dry out in the first year of planting: Apply mulch, water regularly, and get those feeder roots out into the competition. Try hardy cyclamen. You can grow at least half a dozen species and numerous hybrids and cultivars where you garden. Epimediums also make great small, slowly spreading ground covers. The small hairy lip fern (Cheilanthes lanosa) will take drier conditions than many ferns. Also try some hardy ground orchids (Bletilla spp.), corydalis, and-if you have enough light-wild pink catchfly (Silene caroliniana). Or consider planting ephemeral natives. They come up early, do their thing, and then go dormant around July or so. In spring there should be enough moisture beneath those trees for trilliums, bellworts (Uvularia spp.), bluebells (Mertensia spp.)...the list is endless.