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Q: Is the flea beetle cure for leafy spurge going to be a worse problem than the plant itself? We are already trying to deal with flea beetles.

A: Not to worry. The flea beetles that eat leafy spurge are not the ones in your garden. They eat only leafy spurge.

There are many, many types of flea beetles. This one grew up in a part of the world where they and leafy spurge were both native. They developed an appetite only for spurge and don't like other plants.

Scientists working on bugs for biocontrol are very aware of the possibility of introducing an insect that could become a pest in a new ecosystem. They are extremely careful.

They usually begin by testing the insect to see whether it will eat any local plants besides the one being targeted. Testing goes on for at least three years to make sure that they will not be introducing a monster. Only when scientists are sure that letting the bugs loose in the countryside is safe will they begin releasing them on test plots.

Sometimes, of course, the bugs turn out not to be effective. They don't eat enough to make a difference or worse yet, they can't survive in our climate.

So what happens, you may ask, to the weevils that are eating our knapweed? Or to the beetles that are eating our leafy spurge? Once they have eaten all the knapweed and the spurge, don't they start on something else? No. They are specialists and when the weevils run out of knapweed and the beetles run out of spurge, they starve to death.

What typically happens is that the insects do not eat the last plant. In other words, no matter how successful our biocontrol is, we will always have some knapweed and some leafy spurge. They will be few in number and the weevils and beetles, also few in number, will coexist with them and continue to keep the weeds under control. This is exactly what has happened in the ecosystems where they are natives.

Q: Have you ever heard of a flower called masterwort?

A: Yes. It is a very nice perennial and we have some in our gardens, but in this country, it is usually called by its botanical name, astrantia. The word wort, spelled with an o, has nothing to do with a bump. It is just a very old English name that means plant. We consider astrantias to be one of the best kept secrets of the perennial garden.

Probably they are not widely known in this country because they don't live any place where summer nights are hot. Needless to say, that doesn't apply to Montana. Astrantias are very successful here.

The leaves look rather like a shiny delphinium leaves. The flowers are pink, white or dark red, about an inch and a half in diameter. The center looks a little like a pincushion with a rim of pointed bracts. The name astrantia probably comes from the Greek word for star, since the flowers look like many-pointed stars.

They are a carefree plant. They can live in full sun or half-day sun. They don't get diseases and we have never seen any bugs eating ours. They don't even need deadheading in order to keep blooming.

Each flower lasts a long time and can even be cut and dried for winter bouquets. If the flower heads are left to ripen seeds, we have found that a few seedlings will grow. They don't reproduce as fast as we wish they would. Their biggest drawback is difficulty in finding plants or seeds.

Master gardeners Molly Hackett and Georgianna Taylor, whose motto is "Never trust a gardener with clean fingernails," welcome your questions. Send them to: 191 Eastside Highway, Hamilton, MT 59840; call 961-4614; or e-mail tenrecs@aol.com. Please include a garden-related subject line in e-mails.

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