Trees & Shrubs Q&A

Q: I've got a problem with bagworms all over my favorite evergreen tree. What should I do?

A: Picking off the bagworms is your best bet if you've got just a light infestation. However, for heavier infestations, you'll want to use a biological control containing BtK. This is best used when the worms are small. If the worms are larger and you find that you do need a chemical control, you can use an insecticide containing pyrethrin to get rid of ‘em. Keep in mind that it's best if you can get to 'em before late August, which is when they begin to pupate. Once they pupate, they will be protected from the controls.

Q: I'm having problems with black, sooty mold appearing on some of my trees. What can I do about it?

A: This is actually an indication of an insect problem. Black, sooty mold often appears when there is a problem with sucking insects such as aphids, scale, whiteflies, or leafhoppers. They secrete a "honeydew" substance that encourages the mold growth. Taking care of the insects is the best solution. Spraying with a horticultural spray oil can help for scale. Using a good liquid fruit tree spray, or an insecticide containing pyrethrin, may help for the others depending on the type of tree and bug that it is. The folks at your local garden center can steer you in the right direction. Once the insects are gone, the sooty mold will eventually wash away. To speed it along, wash the trees down with 1 cup of dishwashing liquid in your 20 gallon hose-end sprayer.

Q: What is dormant spraying, and how do I do it?

A: Many bugs survive the winter by hiding in tree and shrub cracks and crevices. They hatch in the spring with an appetite that would make a hibernating bear proud! To kill the bugs before they hatch, you should dormant spray in late fall, as soon as the leaves of your fruit, nut, and other trees have fallen. You can use a dormant/horticultural oil from your local tree nursery or garden center to nail them in their tracks. First, mix up a batch of my All-Season Clean-Up Tonic(above), and douse your trees with it to the point of run-off. Then apply the dormant/horticultural oil over the top. Repeat these steps in early spring, before the buds swell up and open. The results will be the happiest and healthiest trees and shrubs you've ever seen!

Q: My evergreen tree sometimes sheds some areas of brown needles it develops during the winter. Come spring it's always looking great again. Is this normal?

A: If you don't see any signs of insects or other problems, then this sounds pretty normal. Needle browning and shedding of older needles is normal with many types of evergreens in both spring and fall. In the fall, it's similar to what happens to deciduous trees when they shed their leaves. The browning that occurs in spring is usually due to moisture loss from the winter winds and/or from sunscald in areas of snow. As long as the tree greens up later, it's not a problem. But to minimize the browning, you can wrap small trees with burlap for the winter. Make sure the burlap does not come into contact with the foliage of the tree. Giving your trees a good, deep watering just before the ground freezes in the winter helps, too.

Q: How should I care for my gardenias?

A: Gardenias really do like a lot of attention. They need full sun or light shade, acidic soil, regular water and feeding, and warm day temperatures with cool nights to bloom. Feed them with fertilizers for acid-loving plants unless the soil where you are located is naturally acidic.

Q: We have had a beautiful lilac that's grown well for many years. All of a sudden though, it's not blooming. What could be the problem?

A: Usually, problems with blooming occur for several reasons. First is light. They need at least 6 hours of sunlight a day. If there is shading from trees or buildings, this can affect how well it blooms. Next is improper pruning. Lilacs flower on the previous years growth. If they are pruned at the wrong time, such as fall or early spring, the flower buds are cut off, and there will be no flowers in the spring. They should only be pruned when they finish flowering. Lastly is fertilization - either too little fertilizer, or too much nitrogen. Nitrogen can cause a lot of lush foliage at the expense of forming flower buds. So if you fertilize, cut back on the nitrogen. And if you don’t fertilize at all, you’d better hop to it!

Q: The leaves on some of my trees turned yellow, then brown, and now they're starting to fall off! What can I do to make my tree better?

A: There are a number of things you can do. First, make sure they are getting plenty of water at regular intervals. Then make sure they are mulched well. Regularly bathing them every 2 weeks with my All-Season Clean-Up Tonic (above) will help eliminate any natural enemies. To seal out dust, dirt, pollutants (including chemicals), sunscald, winter burn, etc., thoroughly soak the trees with an anti-transpirant (can be found at most tree nurseries) just before the real hot or cold weather sets in; it's better than buying life insurance for your plants!

Q: What does it mean to root prune a tree?

A: To root prune, you push a sharp, flat spade in and out of the ground all the way around the plant. This should be done at the “weep line” (the farthest point to which the branches extend) for trees and shrubs. Sprinkle some Epsom salts into the cuts. Next, mix 2 tbsp. of tea, 2 tbsp. of dishwashing liquid, and 1 can of beer in 2 gallons of water. Pour this mixture into the cuts. If you would like to see how this is done, you might want to check out my, Year 'Round Tree, Shrub & Evergreen Care DVD, where I take you through this process step by step.

Q: We're moving soon, and would like to take our favorite tree with us. When is the best time of year for transplanting a tree?

A: Fall is the best time of the year to transplant trees, shrubs, and evergreens because they've quit growing for the year, and have some time to recover from the shock before the next growing season. Early spring is the second best time. To get them off to a good start, give each newly moved plant a quart of the following tonic: 1 tbsp. of tea, 1 tbsp. of whiskey, 1 tbsp. of baby shampoo, and 2 tsp. of fish emulsion in 1 quart of warm water. Then sprinkle a handful of Epsom salts over the soil, and say "nighty-nite" for the winter.

Q: How do I get my trees and shrubs ready for the long, cold, winter?

A: There are several things you should do:

  • Thoroughly soak the area around the plants before the ground freezes.
  • Spread a deep later of organic mulch around them to hold moisture in, and to prevent the ground from freezing in the absence of snow.
  • Wrap the trunks of all young trees with an all weather tree wrap.
  • Coat the foliage of evergreens to the point of run-off with an anti-transpirant.
  • Where appearance is not a concern, set up burlap or other windscreens for smaller trees and shrubs. You can find lots more helpful winter hints and tips in my Year 'Round Tree, Shrub & Evergreen Care DVD.

Q: I was shocked to discover moss and mold on several of my shrubs. How can I get rid of it?

A: You need to spray them to the point of run-off every 2 weeks throughout the growing season with a mixture of 1 cup of antiseptic mouthwash, 1 cup of Chamomile tea, and 1 cup of Murphy®Oil Soap in your 20 gallon hose-end sprayer. For small areas on branches and trunks only, a mixture of one part bleach to 10 parts of water should do the trick.

Q: We have a lilac bush that is about a foot tall. It was doing great, then I caught the neighbor's dog urinating on it. It turned brown, and lost its leaves. Can it be saved?

A: Yes - if you act quickly. First, apply pelletized gypsum all around the plant at the recommended rate. Then give it a good, thorough soaking with 1 cup of dishwashing liquid in your 20 gallon hose-end sprayer. Two to three weeks later, apply an anti-transpirant to the point of run-off.

Q: I have shoots growing up from around the base of a plum and a crabapple tree. How do I get rid of the shoots without killing the tree?

A: If the shoots are suckers, growing from the base of the tree or from the roots, you don't want to use a weed killer. Just prune them out, preferably below the soil line. If the shoots that are growing under the trees are seedlings growing from fallen fruit, use one of the systemic plant controls containing glyphosate, like RoundUp®, at the recommended rate. For super control, overspray the whole area with 1 cup of dishwashing liquid in your 20 gallon hose-end sprayer first - it won't hurt anything, and it will help the control adhere better. Make sure you apply this chemical on a wind-free day, and be careful - the glyphosate kills all that it touches, so spot treat the shoots only!

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