Wasps: The good, the bad and the dangerous

It’s too late to prune azaleas and other spring bloomers

Eileen in Alexandria writes, “I believe the best time to cut back azaleas is right after they bloom. Does that mean that they will not bloom next year if we cut them back now? They are very bushy and starting to really look overgrown.”

You are correct, Eileen. The absolute best and safest time to prune spring bloomers such as azaleas, rhododendrons and lilacs is right after they finish flowering.

Now, we normally have a nice “window” of opportunity for a couple of months after that, but a quick check of my own plants has just reinforced that this year has been everything but normal, as both my azaleas and rhododendrons have already formed the buds that will become next year’s flowers.

Check your own plants, but dollars to doughnuts I say you’re going to see the buds of future flowers. Unless you cut them off, of course.

But you can still manage their size — kind of …

Like many gardeners, Eileen in Alexandria has just noticed that her azaleas have become overgrown. Unfortunately, most of these and the other spring bloomers in our area have already produced the buds that will bloom next spring — so what’s an overgrown azalea owner to do?

Selective pruning. Cut off entire branches, but only the minimum number of entire branches you need to keep the plants in bounds. Do not give azaleas, rhododendrons, lilacs or other spring bloomers an overall haircut or you might remove all of next year’s flowers.

Take your time, study the plant well and only take off a branch or two a day. That way you’re much less likely to experience the heartbreak of pruner’s regret.

It is much easier to take off another branch on Thursday than to super glue and duct tape a plant back together again on Wednesday.

Blue-winged wasps are beautiful and beneficial

Alan in Oxon Hill writes, “I have blue-winged wasps nesting less than six inches away from our home; my son noticed them digging holes in the ground earlier this week. Are they dangerous to children or pets? Do I need to get rid of them or should I leave the nests alone?”

You should absolutely leave the nests alone, and you and your children should welcome these gentle and entertaining visitors, Alan. Although they can look frightening, these large and beautiful ground-nesting wasps don’t sting humans or pets.

They do have stingers, but they only use them on the grubs of Japanese and June beetles, which is why they’re in your yard — they’re killing the grubs that would have eaten your plant’s roots this fall and eliminating many future beetles-to be. Or not to be, as the case may be.
Do bee do bee do. Wasps too.

Blue wasps in ground: good! Yellow wasps: bad!

When I assure Alan in Oxon Hill that the blue-winged wasps nesting near his house are harmless, I speak from experience.

One year they showed up in a community garden I helped establish for The Salvation Army and I spent an entire day walking through swarms of them to assure the gardeners that these wasps only sting Japanese beetle grubs in the soil, not humans, pets or anything else above ground. (And if you don’t believe me, check out what “The Bug Guy” has to say here.

But that is not true of the very different looking — and highly aggressive – ground-nesting wasp known as the yellow jacket. Blue-winged wasps are large, dig individual nests and are, well, blue winged.

If you see a lot of insects that look a bit like honeybees coming in and out of a single hole in the ground, back away slowly and email your trusty garden editor for advice on how to eradicate that yellow jacket nest safely and successfully.

Yellow jackets do sting people and pets. They like to sting people and pets. And that underground nest currently contains hundreds of yellow jackets — a population that will swell to thousands by the end of August.

We’ll do a whole week on them soon. But if you find a nest in the meantime, shoot me an email before you act. Or check out these previous Garden Plots with information about dealing with it.

Wineberry watch: time to pick fabulous fruit that grows wild

It’s prime time for picking blueberries in our area — raspberries too if you grow the right kind and leave first year canes standing to get that wonderful second flush of berries in the early summer.

And there’s a berry just coming into ripeness in our area right now that you can pick and savor even if you didn’t plant it — the misunderstood wineberry.

A once-deliberately-planted ornamental that escaped to flourish in the wild, you see the distinctive arching reddish canes all over our area. Those canes produce flowers that become red pods that are just now opening to reveal bright red fruits that look a lot like the raspberries they’re closely related to.
And those fruits are not only safe to eat, they’re delicious — bursting with a refreshingly different (and very juicy) raspberry-like flavor. So pick and enjoy these fabulous free fruits; just be sure to wear long sleeves when you go picking; the canes are very thorny.


Mike McGrath was Editor-in-Chief of ORGANIC GARDENING magazine from 1990 through 1997. He has been the host of the nationally syndicated Public Radio show “You Bet Your Garden” since 1998 and Garden Editor for WTOP since 1999. Send him your garden or pest control questions at MikeMcG@PTD.net.

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