What is the best tool to use to cut down ornamental tall grass, such as porcupine grass or switch grass? Mine are 10 to 12 feet high. How low do I cut? When should I divide them?
Cut your grass down in spring, leaving about a foot of stem. You can use manual or electric hedge clippers or even a chainsaw on a big stand of grass. Tying off above and below the cut with a bungee cord or rope helps stabilize the grass while you cut. Divide after cutting.
(Porcupine grass is a type of miscanthus. Should a miscanthus self-seed, it needs to be removed, because it has proven invasive in Maryland.)
What is the conventional wisdom on the merits of using a roto-tiller or spading to prep soil for a vegetable garden? It's mostly clay soil.
Roto-tilling or spading improves soil aeration and helps control weeds and insect pests. Either method allows the soil to warm sooner. Both incorporate soil amendments, such as lime and organic matter, down to where roots grow.
Too frequent use of a roto-tiller can create a plow pan, a fluffy layer of soil above a compacted one. A plow pan hinders roots, water and air penetration. Tilling also kills beneficial worms and mycorrhizae, the microscopic fungi that extend roots' surface area.
In any case, be sure your clay soil is dry enough to be workable before you proceed. To test it, squeeze a handful into a ball and bounce it in your hand. If it breaks apart easily, the soil is OK to work. If it stays in a ball, allow the soil to dry further.
Working too-wet clay-based soil destroys its structure. It sets up like cement and can take years to recover.
Checklist
Plan to plant groundcovers this spring where grass won't grow, where heavy shade or tree roots create problems, or where slopes are steep. Select plants based on the amount of sun they require. Don't install rapid growers near property lines or woodlands.
Start rosemary, thyme, lavender, sage, basil and tarragon seeds indoors now. Set outdoors in pots or garden beds in May.
Ellen Nibali, a horticulture consultant, works at Maryland Cooperative Extension's Home and Garden Information Center, and Jon Traunfeld is the director of the Home and Garden Information Center. The center offers Maryland residents free gardening information. Call the center's help line at 800-342-2507 or e-mail plant and pest questions through the Send a Question feature at hgic.umd.edu.