Question #1: I have a few shrubs in my front yard that I thought were hollies. They do have prickly leaves. My friend insists that they are something called osmanthus. Do you know of a way I can tell them apart? I do wonder why I never see red berries on them.
Answer #1: The foliage of hollies and osmanthus does look very similar and can be confused. In fact, one common name for osmanthus is false holly. However, there is an easy way to distinguish one from another. Look to see how the foliage is arranged on the stems. Osmanthus leaves are opposite each other, while the leaves of hollies alternate along the stem. Either way both hollies and osmanthus are attractive landscape plants. If your shrubs are osmanthus they rarely produce berries in cultivation. One bonus though is that osmanthus tends to be deer resistant.
Question #2: What is the best way to deal with trees and shrubs that are covered with either ice or snow? I certainly do not want to cause them anymore harm but sometimes the ice and snow weights down the branches.
Answer #2: Once a winter storm hits it is sometimes better to leave well enough alone. This is true if your trees and shrubs are covered with ice. Disturbing ice laden branches can cause them to snap off. However, if the branches are covered with snow gently brush it off using an upward motion. Use a broom instead of a shovel because a shovel can damage bark. If you have multi-trunk evergreens like some Arborvitae, it is best to tie them up or give them support before a storm strikes.
Question #3: My small gardenia is producing a sticky substance from its leaves. The floor beneath is also covered in a sticky layer of film. It also seems to have some yellow leaves. What could possibly be causing this and how do I stop it?
Answer #3: What you are noticing is called honeydew and is the result of the feeding of some type of sucking insect. The likely culprits on houseplants are aphids, mealybugs, or scale insects. Their feeding damage also causes leaf yellowing. Aphids are small soft-bodied insects of various colors, which cluster on stems or leaves. Mealybugs are covered with a powdery or cottony white wax and are typically found at the leaf axils (where a leaf meets the stem). Scale insects appear as small raised brown or black bumps on leaves, often along the leaf veins or stems, and can be scraped off. Carefully inspect the plant to determine which insect is infecting your plant. Aphids can be washed off with a gentle spray of water, mealybugs and scale can be removed with a Q-tip dipped in alcohol. For heavy infestations, spray the plant thoroughly with insecticidal soap or horticultural oil labeled for houseplants. Sometimes it is best to discard the plant and purchase a new one rather than treating the plant with an insecticide because these types of insects can be difficult to eradicate.
“Ask the Plant and Pest Professor” is compiled from phone and email questions asked the Home and Garden Information Center (HGIC), part of University of Maryland Extension, an educational outreach of the University of Maryland. To ask a home gardening or pest control question or for other help, go to https://extension.umd.edu/hgic
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