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Here’s what’s eating your currant bushes and ‘spitting’ on your wild roses

  • Author: Jeff Lowenfels
    | Alaska gardening
  • Updated: 3 days ago
  • Published 3 days ago

Currants glow in the sunshine on Sunday afternoon, July 16, 2017, along a trail in Kincaid Park. (Erik Hill / ADN)

Aghhh. Lots of questions this week, only these have been asked, year in and year out. I hate to repeat myself more than I have to, but I have found when lots ask, lots of others care, too.

First, right on schedule, are the tons of emails about caterpillars stripping the leaves off gooseberries and currants. If you have one of these plants, you have the problem. If not, you are a rare exception.

Every year I point out that these are not caterpillars, but sawflies. What is the difference? Well, caterpillars are members of the order Lepidoptera. They are the larvae of moths and butterflies. Sawflies, however, are related to wasps and bees, belonging to the order Hymenoptera. They are larvae of special flies.

In addition to not being harmed by Bt products as are caterpillars, sawfly larva eat almost like those sped-up, time lapse films that show an hour of real time in just a couple of seconds. A hatch can strip a gooseberry bush in a couple of days.

Some gooseberry sawflies can go through four generations during a summer. I wouldn't know, as ours are always defoliated in early July by the first hatch. And, this year, I got one email wondering what was happening to the gardener's iris leaves accompanied by a picture of what one would suppose to be the culprit, a caterpillar. These hatch and the eating begins. Then the caterpillars drop to the ground, pupate and emerge as flies that lay eggs, perpetuating the cycle.

By now it is too late to do anything to save the leaves on your bushes. The berries are never eaten and should ripen. Next year, the process probably will repeat itself. Knowing that the eggs are laid on the lower leaves inside the bush suggests hand picking as soon as they hatch, but this has never helped anyone as far as I can tell. And, you can spray with a kitchen soap concoction, but again, this isn't really effective, perhaps because these guys probably can eat a lot even in the short time before they die from your mix!

Yikes! It is one thing to have the leaves stripped off gooseberries and currants. The branches and fruits remain. What about iris plants? Being all leaves and no stems, iris plants are a different thing altogether. Without the leaves, there is nothing left of the plant! And, sure enough, I got a complaint about something eating iris leaves and it turns out to be another kind of sawfly larva.

In England, gooseberries are sacred. As such, there are recommended remedies for the problem and one is the use of predatory nematodes. Get on the internet and take a look around. I am sure some of the companies ship to Alaska. They might even work against the iris-eating types. In addition, talk to your nursery about newer, resistant varieties of both plants.

Next, spittle bugs, which I have also written about many times before, are of great concern. You are not seeing spit all over your wild roses and other plants. These are aphid-like bugs that pump out from their abdomens a liquid-air mixture to produce that "spit." It serves as protection for the insect and it works! Don't worry, however, no damage is done by them or the spittle.

Of course, this time of year there are also a lot of lilac questions. Why didn't yours bloom? Nine times out of 10 it is because a moose came and ate all the buds sometime during the winter. That is why so many only bloom on the top, where the moose were unable to reach.

Why are the leaves on your lilacs curled (and in some cases dying)? It is probably because you used a weed-and-feed product. Lilacs do not respond well to exposure to the weed part of those formulas.

And, finally, this time of year there are the questions about all the mysterious seedlings appearing wherever there is bare soil. They can be growing so thick, one wonders if anything else can grow through them. These seedlings completely cover bare soil. They even appear in pots of last year's soil.

What seems so obvious, alludes us. It is the cottonwood seeds from all the fluff that has been flying. They germinate easily. Some of the questioners are dealing with seedlings from last year's production. These are one to three inches tall and grow very uniformly.

Fortunately, these seedlings are easy to hoe away and once taken down to the soil don't regenerate. Whew! You can also use some sort of weed killer as long as it is safe. RoundUp, in my opinion, is not to be used .

What do I recommend in place of RoundUp? Your first option is to learn to live with the weed if possible. Your second choice is physical removal or control. Steam and boiling water work great on these masses of seedlings. Got an old steam iron? The third choice is to use a liquid spray or drench to kill the plant. There are a lot of options such as ADIOS, horticultural-grade vinegar, clove-based products and corn gluten.

Jeff's Alaska garden calendar

Learn to make miniature fairy flower gardens in containers, or not!: 6-7:30 p.m. Tuesday, July 17, Alaska Botanical Garden

Learn plant pattern painting: 6-7:30 p.m. Thursday, July 19 Alaska Botanical Garden. Wallpaper anyone?

Both classes are $50 for members, $60 for non-members. For more information, call 907-770-3692. (alaskabg.org; 4601 Campbell Airstrip Rd.)

Potatoes: Keep hilling. Next year, let's start them indoors in April. We would have new potatoes by now.

Chickweed: Why are you letting yours go to seed? It is in flower now. Get it out of the garden.

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