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When and how do I trim my boxwood bushes? They are getting too large.

Spring is the best time to prune your boxwoods, although you can safely prune them until early summer. Avoid pruning them in late summer or autumn.

Start your pruning by removing anything that is dead, badly damaged or disease. Once you’ve done that, you can reduce their size by removing some of the longest branches back to the branches they’re growing from OR back to shorter branches that are growing lower down on those long branches. Don’t just cut the branches back part way, leaving stubs. For well-established shrubs like yours, you can remove up to one-third of the branches this year. If your shrubs are still too large, it’s best to wait until next year when you can safely remove another one-third of the branches without causing plant stress and stimulating unhealthy growth.

Your boxwoods will have a nicer shape if you’ll stop after each cut and check the overall appearance of the shrub before making your next cut.

Size isn’t the only reason a boxwood may need pruning. A boxwood’s evergreen leaves are easily damaged by our dry winter winds. Leaves and twigs can become dry and bleached. Removing the damaged twigs and branches can improve the health and appearance of a boxwood if the damage isn’t too extensive.

Courtesy Meredith Seaver

I’ve had worms in my apples for five straight years now. I believe it’s the codling moth. Can you help me?

Apples and pears need protection from the Codling moth that causes “worms” in the fruit. If you do nothing, you may lose a large percentage of your crop. If you’re diligent about protecting your fruit throughout the season, you’ll have a healthy harvest. The worms in apples and pears are actually caterpillars, the larvae of the codling moth. This moth lays her eggs on the fruit or leaves that are close by and the larvae tunnel through the fruit to the core to feed on developing seeds.

Outside of individually bagging your apples to prevent egg laying, the options for protecting apples and pears involve spraying. There are conventional and organic options that are effective.

You can estimate your start date for spraying your apples by watching your trees. The traditional start date is about 10 days after the petals drop from the blossoms. Or you can subscribe to our free email pest management advisories for a more precise starting date. Like all insects, codling moth development is dependent on temperature. The Integrated Pest Management team monitors weather, temperature, and trapping to forecast the dates when codling moths will be mature and beginning to lay eggs. The advisories provide recommended spray dates and include information about spray products that you can use and how often you need to spray them. The dates are specific to different areas and counties in Utah. You can subscribe to our free email advisories at http://pestadvisories.usu.edu/subscribe/ and get up-to-date information about many pests and diseases throughout the growing season.

Also do a thorough cleanup under your trees each fall and make sure you aren’t leaving any fruits on the ground or on the tree.

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Can I use dormant oil to prevent wormy apples?

People often refer to dormant oil applications as “dormant spray,” but the spray is more accurately called a delayed-dormant oil spray because it’s applied just after the trees break dormancy.

A delayed-dormant oil spray (done when buds begin to swell) won’t really help with the codling moth, but it can make a difference with the size of the aphid and mite populations you may need to deal with during the season.

Using horticultural oil for Codling moth control during the growing season only gives fair results and needs to be repeated every three days. There are more effective options that are applied less frequently. Whatever you choose to use, the timing is important. There’s no need to do any spraying before adult moths are active and laying eggs, but once it’s time to start spraying you must be consistent if you want to get worm-free apples.