Are Colocasia esculenta plants poisonous to cats? I want to purchase more plants, but how do I tell whether they are poisonous before I buy?
The foliage of Colocasia esculenta, commonly known as elephant ears or taro, contains the irritant calcium oxalate. Although potentially toxic, the immediate effects of this compound are oral pain and irritation. Consequently, any animal that attempted to eat some of the plant would feel the oral discomfort long before a toxic amount could be ingested. The tuber of taro is nontoxic and actually a staple food product in many parts of tropical Asia. For lists of toxic and nontoxic plants, go to the Web site of the American Society for Prevention of Cruelty to Animals at www. aspca.org or call your veterinarian.
When is the best time of year to apply lime to my lawn?
You can apply lime at any time of the year, even winter, as long as the soil is not frozen. It usually takes at least a season for lime to have an impact on the pH level of your soil, so it's good to have a soil test done and plan ahead. Download or request our publication HG42, "Soil Amendments and Fertilizers," for information on the type of liming products available.
The branches of my eight-year-old walnut tree splay out like umbrella spokes. How do I prune it and when?
It is best to prune trees during their dormant period. Normally, nut trees require little pruning, and it is done primarily to form a strong framework of branches. "Umbrella spokes" is not a strong framework. As a tree develops, scaffold branches (main ones off the trunk) should have a vertical distance of 18-24 inches between them. First, prune any dead or crossing branches back to a major limb or to the trunk. Then remove scaffold branches with the most narrow crotch angles (less than 40 degrees) because they are weaker. You can leave one or two of the "spokes" and encourage others at staggered intervals up the trunk, but this will need to be done over a period of years because you should not remove more than a fourth of the tree's canopy at a time. The growth of a young tree depends on the number of leaves that grow each year.
Jon Traunfeld, regional specialist, and Ellen Nibali, horticulture consultant, work at the University of Maryland Cooperative Extension's Home and Garden Information Center. The center offers Maryland residents free gardening information and answers to plant and pest questions. Call its hot line at 800-342-2507 (Monday through Friday, 8 a.m.-1 p.m.) or e-mail questions to www.hgic.umd.edu. (You can also download or order publications and diagnose plant problems online.)
Checklist
1. Gently sweep snow off shrubs and small trees to prevent winter injury.
2. Beat the winter blues by walking around your vegetable garden to map out plans for 2005.
3. Note the areas of your landscape that receive salt and salt spray this winter. You may need to flush the salts out of the soil this spring with fresh water.