Ask the gardening expert

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For the second year in a row the Shasta daisies are falling over in my garden. They seem taller this year, is that why they are doing that? The first year they seemed shorter. Does the fact that they are tall have anything to do with it?

I do feel the tallness had everything to do with it. They are such a wonderful plant. Leucanthemum X superbum, as they are now called, ( formerly named Chrysanthemum x superbum), the Shasta daisies are an ever-popular bright blooming garden beauty. When there is abundant moisture all springtime they are going to grow tall, and then can become so tall they can't take even the lightest breeze and continue to stand. The garden books tell you to stake them, but what a chore and it often is too late once they began to topple. There is a way around that frustrating job but it requires you to pay attention to their growth early on. In early to mid-June, pinch or cut back nearly half the plants randomly, to different heights, then around July 15 cut again. Just a few, leaving staggered heights again. They may bloom a little later, but at all different times and heights, on sturdier stems that are not so tall that they fall over in wind or rain. Just dead-head as usual. You'll have daisies all mid- and late summer too. We've been pinching our garden mums forever, but maybe hadn't thought of trying this on other perennials, but it works!.

Here are some other perennials I've had success with cutting a few here and there to delay bloom and had shorter stronger, stems: Asters, Joe Pye weed, penstemon, tall phlox, rudbeckias, echinacea and linaria.

There are so many different colors of hydrangeas in the garden stores. I used to see only blue ones in my grandmother's garden, now I see red, pink, purple and white. What's going on here?

Yes, isn't it just wonderful? There has been an explosion of new varieties in just the last few years. Every time we hit the garden center there are ones that we may not have seen. I own two books written by Britons on hydrangeas. The first is a 1997 Timber press title, "Hydrangea: A Gardeners Guide" by Toni Lawson-Hall and Brian Rothers. The other is a 2007 book published by Firefly Books, "Complete Hydrangeas," written by Glyn Church.

They both say the same thing on keeping or changing colors of the blooms. They agree that horticultural science does not know why one can manipulate the color of hydrangea blooms, but they do know how to do it! The majority of the species that may be manipulated are the macrophylla. Church's observation is so true; he says we always want what we don't have. In Britain with its alkaline soil folks want blue blooms that require acid soil, while here in the Western U.S. we have acid soil, so we think that pink blooms are what we need.

We see the pink varieties from the florist industry and plant them only to notice that in the next few growing seasons the are reverting to blue. That's acid soil for you! With a good deal of work and time spent you could force the big leaf variety to turn to a pink or red shade. Both books tell you how to go about the color-altering operation. Church says the easiest way is if you want pink, buy a pink bloomer, and keep it that way by growing it in a container using some lime in the potting mix in spring and summer. He cautions to be careful not to use too much lime at one time as it can cause chlorosis, or leaf yellowing. Church goes on to say to not use your garden soil in the container as it packs down too hard and the roots need air so use a fluffier soil that allows air to aid in soil health. Another easy way is to use fertilizer that has plenty of phosphorous; again he cautions against too much, too soon.

Incidentally, it's noted that white hydrangeas (with a few exceptions) always stay white.

Celeste Lindsay is a WSU-certified master gardener. Send questions to mslindsay8@gmail.com.

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