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Making It Grow! News Articles

June 5, 2005

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Thomas Jefferson kept journals of his gardening experiences, noting all the factors that came into play at his mountain top home, Monticello. South Carolinians who follow his example are busy with pen and paper as we continue to enjoy days of unseasonably cool weather. Memorial Day had us scrambling for sweaters instead of our usual bathing suit attire.

Question: I have variegated privet under my dining room windows, or rather in front of them as it has gotten to be over ten feet tall. To add insult to injury, the leaves are covered with a black film and the whole plant exploded with little flying insects when I tried to prune it back. I'm about ready to pull it up and start over. What do you think?

Answer: Variegated Japanese privet, Ligustrum sinense, is often sold as a foundation plant. Unfortunately, it easily reaches ten to fifteen feet in height and if pruned, regains that size very quickly.

Those pesky white flies take the blame for the black leaves. The immature insects feed on the undersides of leaves; their waste falls on the tops of leaves below and is a wonderful medium for a black mold to grow on. This is the same interaction between plants and insects that causes the yearly infestations of the beautiful gardenias. Your local Extension office can recommend products that will kill the white flies, but with the size privet that would be quite a spraying job.

Your original idea of replacing this plant might be your best bet.

Privet, which can be so attractive in a nursery setting, is now a leading culprit on the nonnative invasive species list. The variegated and all-green forms of privet flower with profusion, and those sweetly scented panicles become millions of seeds which are devoured by birds and then deposited in every corner of our state.

Many of our woodlands are now completed covered with thickets of privet which crowd out our native plants. Between the yearly spraying for white flies and the yearly pruning tasks, you might prefer to choose a plant that will now when to turn off the growth hormones and free you up to enjoy some leisure time in your yard. If you shop with a locally owned nursery, the owners can help you choose a plant more suited for growing next to your house.

Question: My hydrangeas are finally putting on new growth and flowers but much of it is coming from below dead wood. Should I have pruned back these plants last fall? They look so strange with all these naked branches above the succulent new leaves.

Answer: Pruning hydrangeas is slightly tricky in that you may cut off next year's flowers if you don't do it exactly at the right time.

Many gardeners prefer to take your approach—once the new growth appears you can safely cut off any dead wood and discard it. You don't have to wait until the growth is large, look for those small swelling buds next year and you will be able to tell exactly where to cut to remove dead wood. If your plants are getting too tall, it is safe to prune immediately after they flower. Remember that hydrangeas respond well to applications of organic matter. You may want to top dress them with cow or mushroom compost and then reapply that all important mulch that will help hold in the soil moisture.