What's behind dogwood's lost blooms

Q: What could be the reason for fewer blossoms on our 30-year-old pink dogwood tree?

A: Because you don't say otherwise, I'll assume your dogwood is generally healthy. If there is no leaf die-back (leaves turning brown and withering at the edges) or other signs of anthracnose or other disease, then there might be other reasons your tree isn't flowering well.

Has the area around your dogwood grown shady? Although dogwoods prefer partial shade, flowering is reduced in heavier shade. Often trees have grown large around established dogwoods, so they're living in deeper shadow than we realize.

If you pruned in late winter or spring, you've removed flower buds. Dogwoods should always be pruned during the summer after they flower so the next year's bloom isn't removed.

If your tree wasn't adequately watered last summer, last year's drought could cut down on this year's bloom.

Winter cold can kill flower buds. This may be the most likely reason of all, especially if you notice other dogwoods around town with scanty bloom. That exceptionally hard freeze we had in the middle of February may have hit just as buds were beginning to develop.

Dogwoods grow and flower best when fertilized annually and watered regularly, and in locations where they don't need to compete with grass and other plants for nutrients and water.

Q: I read the March 12 issue of Pacific Northwest magazine about a garden that contains gooseneck loosestrife. Back in Colorado, where I moved from, I learned that no one should plant loosestrife because it can take over wetlands. Is the gooseneck variety less invasive?

A: Just like with people, many plant families have one or two renegades in the bunch that cast a shadow over their relatives. Such is the case with loosestrife, which has 500 different species in its extended family.

Purple loosestrife (Lythrum salicaria) is a noxious weed, one of the most aggressive invaders, taking over wetlands and choking out native species. It's banned in most states including ours, along with garden loosestrife (Lysimachia vulgaris).

Gooseneck loosestrife (Lysimachia clethroides) is a different species. Its common name comes from the unusual curve of its white flower head, which brings to mind the crook in the neck of a goose. While gooseneck loosestrife spreads in damp soil, it can be contained by planting in drier areas of the garden, where it doesn't spread enough to create a problem. It's a lovely plant to grow in a pot, or to cut for arrangements, for its unusually shaped flower is beguiling viewed up close.

Q: We've inherited my mom's 50-year-old Daphne odora and are considering transplanting it to my brother's place in Portland. Nursery folks advised him not to because the plant is so finicky. I've transplanted it twice when we moved Mom, both times with success.

Our decision rests on your word. Should we let sentimentality rule us and try to move it again? Or let it stay where it thrives so that the new owners of Mom's place can enjoy it as we all did for so many years?

A: Daphnes are tricky, and not a plant to push your luck with. Most gardeners have stories about daphnes that have grown large, and others that have died suddenly for no apparent reason.

I'm very impressed you moved it twice successfully. If it were me, I wouldn't trust fate a third time. I think it'd be worse to kill a plant you feel sentimental about than to leave it behind for someone else to enjoy.

Since daphnes are easily obtainable, not particularly expensive and grow fairly quickly, why not leave this one for the new owners and buy a new Daphne odora to remember your mother by?

That way you'll feel good knowing your mother's plant is still alive in her old garden. And when you inhale your new daphne's supreme fragrance next year, it'll invoke the same sweet memories as if you were smelling the original.

Valerie Easton also writes about Plant Life in Sunday's Pacific Northwest Magazine. Write to her at P.O. Box 70, Seattle, WA 98111 or e-mail planttalk@seattletimes.com with your questions. Sorry, no personal replies.