Dead or alive? How to test your trees and woody shrubs

DEAR JESSICA: I purchased a small lemon tree this summer and kept it indoors. Unfortunately, it dropped all its leaves so I cut it back. Is there any chance that it will come back? Or am I holding onto a dead plant?

— Susan Weine,

Bellmore

DEAR SUSAN: It’s not uncommon for lemon trees to drop some leaves over winter, but a severe leaf drop like the one you’ve described can usually be attributed to extremely cold temperature, overwatering, underwatering, a lack of light or a nutrient deficiency.

You can check for root rot, a result of overwatering, by gently slipping the tree out of its pot and examining its roots. If they are firm and light in color, they are healthy. Dark and/or mushy roots indicate rot. Most often, when this occurs, there is little that can be done to save the plant because rotted roots cannot adequately transport water and nutrients throughout the plant, nor can they usually recover. But if the rot isn’t extensive, you can try trimming it away and replanting in fresh potting mix. During winter, allow the soil to dry out between waterings; during summer, your plant’s active growing season, keep the soil moist but not soggy.

Because your plant is indoors, cold isn’t likely to blame, unless you keep it near a drafty window. Citrus plants also require a minimum of six hours of direct sunlight daily, so they should be kept in the brightest available spot in your home.

To maintain proper nutrition, fertilize every six to eight weeks with a product specifically formulated for citrus plants.

I can’t tell you whether your tree is already dead, but I can help you determine that for yourself. This scratch test can be applied to any tree or woody plant to ascertain whether it is alive: First, gently bend each branch. If it is brittle and snaps easily, then at least that branch is dead and should be removed. Branches that are somewhat flexible when gently bent show promise. Next, scratch into the bark on the tree’s trunk (not a branch) with a knife or your fingernail and take note of the tissue within. If it’s fresh and cream or green, the tree is alive. If it’s dry, brown and brittle, the tree is likely dead.

DEAR JESSICA: I need to prune my climbing hydrangea, which has gone ballistic. How far down should I prune?

— Joyce B.,

via email

DEAR JOYCE: Left unpruned, climbing hydrangeas can reach heights of more than 50 feet, so they certainly can become “ballistic,” as you’ve noted. Unruly vines can be trimmed in late summer, as long as you do not remove more than one-third of the plant.

However, if the woody vine has become damaged at the top, or the overall plant has become leggy, a rejuvenative, hard pruning may be in order, and should be done in late winter or very early spring, just before the plant comes out of dormancy. To do so, cut most of the plant back, leaving just three to five 3-foot-tall stalks.

DEAR JESSICA: My mother, who is 90 years old, has a Dieffenbachia plant that I believe was originally my grandmother’s. I am now caring for it. Since this photo was taken, the plant has become so tall so rapidly that it is leaning over and touching the floor. New shoots keep growing from the base. I can’t bring myself to get rid of it, but it has become out of hand. My daughter will take the pot with the new shoots, but what am I to do with the plant? I would hate to toss it. Are there places or people that take plants?

— Elaine Zetlin,

Long Beach

DEAR ELAINE: Unfortunately, I am not aware of any group or organization that adopts houseplants. You might try posting to your community Facebook page to spread word to any neighbors who might be interested in taking your Dieffenbachia. I have a feeling you might get lucky there.

Regardless, giving your daughter the shoots sounds like a lovely way to keep this heirloom in the family.

As far as the mother plant goes, if you are unable to find any takers and are forced to discard it, the best way to do so would be to compost it or recycle it with your yard waste.