Flower garden design idea using progressive heights

The answer to the perennial garden conundrum of where to put which plants is simple: progressive-height plantings, short to tall, front to back.

As each winter draws to a close, and long-awaited spring sunlight plays across the dormant flower garden, gardeners everywhere begin to imagine lush and lovely greens, blues, reds, purples, yellows, oranges and pinks, filling up those now-empty spaces in perfect symmetry or, at least, in semi-planned floral chaos.

But how to design your garden space so that your exuberant delphiniums don't choke out those lovely little gypsophila? And where to put that new spirea to avoid sun-starving the petunias?

The perennial garden conundrum of where to put what has a sweetly simple solution: progressive-height plantings. And it's even easier than it sounds!

In Step With the Seasons ...

The first basic rule-of-thumb to know when designing a progressive-height garden is that typically, plant height is tied to the amount of time it has to grow.

Plants that have a longer growing season, and grow when the sun is at its strongest, tend to be taller. Plants that grow quickly, emerge in early spring and don't have the benefit of lots of strong sunshine are typically shorter.

But that doesn't mean you have to wait until next fall to enjoy your talls and shorts together! Here are two different ways to design your flower garden around a progressive-height plan:

1. For Smaller Spaces: Be Perennially Blue!

There's nothing like the lovely, airy, old-fashioned delphinium (Delphinium) to anchor a progressive-height garden. That's partly because these spectacular floral spires are now offered in a wide assortment of shapes and sizes. By choosing a blue-and-white tableau, your earthbound garden will mirror the white cloud-flecked blue skies of deep summer.

You'll want to set aside a garden space about six feet long and four feet wide. If your space isn't backing up against a fence, insert a few sturdy posts at the very back of the garden to provide support for the tallest plants, if necessary.

At the very back, plant a row of the gloriously intense, blue Delphinium elatum 'Blue Skies.' Its magnificent spires typically reach five feet high. Contrast that row with a row of its cousins, Delphinium 'Belladonna' and 'Bellamosum.'

The 'Belladonna' offers three-to-five-foot spires covered with lightest blue florets in mid-summer. 'Bellamosum' reaches the same height, but with a profusion of deep, dark blue flowers.

Front the sleek delphiniums with a broad row of Balloonflowers in a striking blue and white mix. The blues (Platycodon grandiflorus 'Mariesi') will reach a typical height of about two feet by mid-to-late summer. The whites (Platycodon grandiflorus alba) are of equal height, and both contrast nicely, with their sweet, saucer-like faces nodding gently on green stems.

A front border of fluffy white sweet alyssum, barely three inches high and massed like a long, white cloud, will provide a fragrant and quick-blooming carpet beneath your perennials' feet!

2. For Larger Spaces: Old-Fashioned Pinks, Purples and Mauves

For a spreading, fragrant, old-fashioned garden, choose a space at least 20 feet long and six to eight feet wide. This is a perfect space to create a two-tier, progressive-height garden, splitting the tiers with a set of stony footpaths. You can interplant the stones with ground-hugging thyme and sweet santolina, giving your visitors a gentle fragrance of summer with each step.

In the background, anchor your garden with a Butterfly Bush (Buddleia davidii 'Black Knight'), a rich, deep purple bush that will attract butterflies to your garden all season long. With a height of between 8-15 feet -- and an ability to spread an equal distance -- this garden fixture produces lush, deep crimson florets on wand-like arms that butterflies can't resist! It will bloom gloriously through the summer and into the fall.

Hummingbirds will join your butterfly crowds if you grow a long row of luscious, tall old-fashioned hollyhocks (Alcea rosea) in front of the butterfly bush. These wonderfully vibrant six-foot spires yield dozens of bell-shaped blooms, five inches wide and more, their pink, red, purple and white blossoms a magnet for tiny, flitting hummingbirds.

For a contrast in both color and texture, front the hollyhocks with a planting of Delphinium elatum, a five-foot-high spire of small-faced florets in purple (D. 'King Arthur') and lovely mauve (D. 'Astrolat').

Run a classic stone pathway, just wide enough for you to meander for a fragrance-filled quiet walk, between the delphiniums and a row of lovely, rosy foxgloves (Digitalis purpurea), which will form the back border of your second tier.

The summer-blooming foxgloves rise from a huddled, green mound of soft green foliage, along spikes that rise four feet high and higher. Their bell-shaped flowers will also offer nectar for your butterflies and hummingbirds.

Next up in this tier is an annual: the daisy-faced Cosmos. The hybrid Cosmos sulphureus will stretch to about three feet high, with profuse yellow, orange and deep red flowers. If you can't find this summer-bloomer at a garden center, start the seeds indoors about six weeks before the last frost, or outdoors after the threat of frost has passed.

For your two-tiered, progressive-height garden front row, choose the elegant Bleeding Heart (Dicentra), which will actually thrive in the partial shade. Deep pink, heart-shaped flowers characterized by the tiny white teardrop in the center will bloom from spring until fall on the Dicentra eximia, which will grow to a height of about a foot to 18 inches tall.

No matter what you choose for your progressive-height gardens, remember that it will never look exactly the same from year to year. Delphiniums tend to grow in shorter in their second season than in their first; lilies will grow shorter as well, in seasons when they receive less sun.

But variety and surprise are among the many joys of gardening! Plan the garden you want and know you'll enjoy, and the design will take care of itself!

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