My bean, squash, cucumber and pepper plants are stunted and yellow in color. We cut down a huge maple tree and tilled all the wood chips from the cuttings into the garden to improve the soil this spring. The garden has produced well in previous years.
The wood chips are the culprit. Fresh wood chips are very high in carbon and low in nitrogen. Micro-organisms use nitrogen to break down the wood chips, robbing your plants of nitrogen. This only creates problems in the early stages of decomposition. The remedy is to supplement the nitrogen loss by adding nitrogen fertilizer. Very fresh wood chips can also emit volatile compounds toxic to plants. We recommend aging new wood chips for 6-12 months before using them around plants as mulch or soil amendment.
What is the thorny, nonflowering vine climbing up my trees and through my fence? I spray every year with glyphosate but can't rid of it completely. It's evergreen, with shiny leaves.
Greenbriar is a desirable native vine, in natural areas, and feeds wildlife. However in ornamental landscapes, mature greenbriar can be objectionable and difficult to eliminate. Herbicide does not adhere well to the glossy foliage, unless a spreader-sticker is added to the herbicide. An efficient and economical way to tackle woody plants like greenbriar is to cut down the stems and apply high strength glyphosate or triclopyr to only the freshly cut stem within 5 minutes. Early fall is a prime time to apply herbicide to leaves or stem because it translocates well to roots then. Greenbriar is especially hardy because of a nutlike nodule on the roots that stores energy and can reach inches in diameter. It must be dug up when all else fails.
University of Maryland Extension's Home and Garden Information Center offers free gardening and pest information. Call 800-342-2507 or send a question to the website at extension.umd.edu/hgic.
Plant of the Week
Tuck this perennial "fruit" into a flower or vegetable bed. Rhubarb can pass for a big-leafed hosta and also be handy for harvesting its delicious sour stems. Rhubarb wants full sun to light shade — not too hot. Given average moisture, established plants tolerate drought, but "wet feet" cause root rot. Rhubarb produces for many years, so amend your soil heavily with manure or compost before planting. Varieties are available with red or green stems, so be sure you're buying the color you prefer. Plant crown divisions in early spring, allowing 4-foot-square space for each plant. Wait a year before harvesting and always remove flower heads that divert its energy. After tops die in fall, mulch with more compost. —Ellen Nibali