July is the month of red, white and blue. Patriotism soars. Gardening starts getting difficult as the temperatures reach triple digits. Kate Smith's voice soars. Okay, that sort of dates me.

Back to the red, white and blue. Red and white are easy colors to add to the garden. There are a slew of red flowering plants and red leaf plants. Red is one of those warm or hot colors. To be honest and blunt, it's a sensual color. It's passionate.

White is on the other end. It's a cool color. It's snow and ice. It's a "not tonight" emotional signal. While red is drama and excitement, white is cold. White is also one of the few colors that show up well at night. All else being equal, white is the most dominant color. The eye is attracted to it.

Which leaves us blue.

Blue is another cool color. We think of water and sky, though most of us know that water is essentially clear, and the blue color is really the reflection of the sky.

Blue is not a strong emotional color. It doesn't jump out at you and say "Wow!" Nor does it create a yawn. It stimulates a sense of protection, something familiar. It's more of a "kick your shoes off and sit down" effect. It's a comfortable Lazy-Boy. It's relaxing and calm.

If you remember your basic art class, you'll recognize that blue and yellow combine to give us green. And green is the most prevalent color in the landscape. Basic art class also teaches that colors side by side on the color wheel (and blue and green are) go well together. Yellow and green do well together, purple and blue, purple and red, red and orange and orange and yellow.

Gardeners have known this fact forever. But they also realize that blue is the most difficult color to find in the landscape, next to pure black. True blues are hard to come by. Most seem to be more purple than blue.

Blue flowers tend to be more available than blue foliage plants, though just about everyone is thinking about blue spruce trees and blue hostas. Now, this gets tricky here. Just bear with me. Many of the blue foliage plants, including the two mentioned above, aren't really true blue. Take a wet cloth and rub the needles. You'll see the blue color disappear and you're left with a green needle or leaf. Of course, a green spruce is just not thrilling, and green leaf hostas tend to be a dime a dozen.

That blue is actually something called "bloom." Yep, the same thing as a flower. Imagine the confusion you can create with some people, especially with teenagers. It's fun.

If you are truly observant, you may have noticed that blue spruces and hostas are bluer in the spring than in the fall. That's because rain and bright sunlight destroy the bloom on the leaves. The needles are bluer on the north side of the tree in the fall than the south side.

And for some reason, the "bloom" on the hosta leaves tends to be unappetizing to slugs. Remove it, and the slugs send out signals that say "smorgasbord."

The blue flowers, though, are what gardeners are after. So, here's a partial list.

First, the annuals: lobelia (shade), browallia (shade), petunia, morning glory, pansy, ageratum, Scaveola, statice, Osteospermum, salvia, asters and Torenia. Some come in other colors. And I'm sure you're shaking your head saying, "just what is that plant?" Understandable. Many are newer introductions to the bedding plant world, coming out of South Africa and Australia. As you can see, the annual list is limited. But some of the blues are true blue.

The perennial catalog is a little longer, though it's all relative: Aquilegia (columbine), delphiniums and larkspurs (probably the truest blues), Baptisia (false indigo), Campanula (Canterbury bells), Nepeta (catmints), asters, Centaurea (mountain bluet), Echinops (globe thistle), Eryngium (sea holly), true Geraniums, Virginia bluebells, forget-me-nots, Caryopteris (false spirea), Perovskia (Russian sage), Stokesia (Stoke's aster) and Veronica.

Combine both lists and you'll have some interesting color throughout the seasons. Throw in some bulbous hyacinths, grape hyacinths and squills, and you can extend your blue garden a little longer. And don't forget the blue hostas. Just remember to keep them in the shade.

David Robson is an Extension Educator, Horticulture, at the Springfield Extension Center, University of Illinois Extension. You can write to Robson in care of Illinois Country Living, P.O. Box 3787, Springfield, IL 62708. Telephone: (217) 782-6515. E-Mail: robsond@mail.aces.uiuc-edu

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