Late Summer and the Perennial Garden

Mind the Gaps

Filling the Holes in Your Late-Summer Perennial Garden

By Kathy LaLiberte

Purple coneflowers (echinacea) provide color for a long season: from midsummer to frost.
It's hard to imagine my garden without Oriental poppies, Jacob's ladder, bleeding heart and sweet William. Each has its own beauty and charm, and I eagerly anticipate the fleeting, early summer flowers.

But when bloom-time is over, these perennials call it quits and all but disappear until next spring. A place in my garden that was lush and colorful last week is suddenly dark and empty. Other awkward gaps also start appearing in midsummer. A new plant may not get as big or as full as expected. Pests or disease can cause problems. An old plant may weaken and die.

In a perennial garden, these late-season gaps are almost impossible to avoid. Public gardens with large perennial borders, keep their staff gardeners busy all summer, filling gaps with fresh plants. And I know from my own experience, that when catalogs and magazines photograph a summer perennial garden, there are always extra plants in the wings, waiting to step in.

Here are a few of the techniques that I use to fill, hide or disguise the midsummer gaps in my own perennial garden:

Datura is an annual that's capable of filling a large gap with silvery-green leaves and huge, white flowers.
Add a few annuals. Unlike perennials, annuals have just one year to live and they usually make the most of it by growing quickly and flowering abundantly from midsummer right up to frost. By using annuals to fill some of the gaps in your perennial garden, you'll add color as well as foliage.

These days, most good-size garden centers maintain an inventory of annuals right into early August. Increasingly, you'll find annuals in bigger size pots, too. The 2-quart or gallon-size "jumbo annuals" usually suffer little if any transplant shock when you move them into your garden. Just make sure they get watered frequently for a couple weeks while their roots are getting settled into your soil.

Don't fail to consider some of the great foliage plants available these days, such as coleus, plectranthus, fancy-leaved cannas and other tropicals.

To learn more about which types of annuals work best in perennial gardens (and why you'll probably want to avoid petunias and zinnias), read Late-Summer Flowers.

When you're weeding a perennial border, the gaps become obvious. Solutions can be annual or perennial.
Add some perennials. By midsummer, most nurseries and garden centers have put their perennials on sale. Another good thing about shopping for perennials in late July and early August, is that it's easy to see what's in bloom at that time of year. Picking up a few new perennials will help you fill the gaps in your borders, while introducing good, late-season color that you'll enjoy in subsequent years.

Acquire more fall-blooming plants. There are some perennials that look their best in August and September. Since most plant-buying happens in May when these fall-bloomers don't look like much, chances are good that you could use a few more of them in your garden. So while you're cruising for deals at your local garden center or nursery, consider picking up some mums, tall and short asters, Autumn Joy sedum and a monkshood. If you're lucky, you might also be able to find flowering kale or flowering cabbage. These plants can look a little batty early on, but you'll be patting yourself on the back in early November.

Move in some pots. At the beginning of the season, I usually pot up a dozen or more decorative planters. Of course it's not that I "need" or even have room for that many pots. There are just so many interesting plants suggesting so many wonderful combinations, and I have accumulated so many great pots! If you have a couple extra mid-size containers around, try using one of them to fill a gap in your perennial garden. You can't do this more than a few times throughout the garden, and not every planter will work, but you might be surprised by how well it works. Look closely at the gardens featured in magazines such as House and Garden, Horticulture and Martha Stewart Living, and you'll see how often they use this technique.

Move the art around. I have a couple large, stainless-steel globes in my garden. I also have several birdhouses and two small stone water basins. And I also admit to having a few life-size concrete turtles and bunnies. It might be a bit presumptuous to call these accessories "garden art" but that's how I think of them. I also consider benches, chairs and birdbaths garden art, and in my garden, almost all of these features are mobile.

The stone basin that looks great next to the primroses in early spring, would get completely hidden by the hostas, so I move it into the gap left by Jacob's ladder. I use the steel globe in the same way. A large one remains in the shade garden until the hostas and lady's mantle fill out, then it's available for hiding problems elsewhere. When all else fails, sometimes the best strategy is to just draw the eye away from the problem and let it rest on something like a sculpture or bench.

second article...

It's August. It's hot. And the weather is taking its toll on your garden. What's a poor gardener to do? Here's how to beat the summer blahs and give your garden a second life.

Summertime is made for outdoor pleasures—for impromptu picnics on the lawn, lazy afternoons on the front porch, alfresco dining under the trees. Is it any wonder then that we want to make our gardens last through the final weeks of summer—and beyond?

But come the dog days of August, gardens tend to slump. "Everything just looks tired and bedraggled," complains one beleaguered gardener. "Either spider mites are spotting the leaves or else the leaves are just turning brown and falling off."

Experienced gardeners ward off the summer-garden doldrums by advance planning. Master Gardener Fred Rheingold of Rheingold Farms in upstate New York extends his season by planting foolproof summer bulbs like caladiums (perfect to brighten up a shady spot), Oriental lilies and enormous dinner-plate-size dahlias in May and June. But if you haven't planned ahead, what are the quick fixes you can make right now to get your garden back on track and keep it beautiful and blooming through fall?
BRING ON THE COLOR!

There's nothing like instant color to perk up a tired-looking summer garden. Adding vividly colored, full-size plants just coming into bloom is a great way to get that boost, suggests Rheingold. Because late summer is an ideal time to buy discounted plants, try filling in bare spots with colorful additions from your local garden center. “Past-their-prime annuals can be replaced with fresh blooms like lilies, fuchsias, ornamental grasses and hydrangeas,” he advises. Or go for brightly colored summer bedding plants like marigolds, petunias or impatiens.


ADD MOVABLE CONTAINERS

Adding potted bulbs and container plants are other quick-fix solutions. Because they're portable, potted bulbs like angel's trumpets can be moved around the garden as color accents, filling in gaps in your beds and borders. Some gardeners prefer colorful container plants like brilliant red or bright pink geraniums (which also have a wonderful scent) or coleus (enjoying a revival right now) and place them along the garden sidelines so they're easy to move into bare spots as needed.


CONSIDER COOL-SEASON FLOWERS

Another way to add a burst of color to a fading summer garden is to plant a bevy of cool-season flowers. Charles Nardozzi, a senior horticulturist with the National Gardening Association, suggests planting pansies, violas, primroses, snapdragons and chrysanthemums at the end of the hot summer. “These will flower until the first freeze, and some pansies and violas will even endure temperatures as low as 20 degrees F.” Or consider a lush fall foliage tree, he adds. Nurseries today carry spectacular foliage trees such as maple or dwarf crape myrtles, which sport beautiful red blooms in late summer and stunning maroon foliage through fall.


GET RUTHLESS

Most of all, though, you've got to be ruthless when the season's hot, humid weather wreaks havoc on your precious plot. Otherwise, it could promote wilt diseases, outbreaks of spider mites, other insects or various types of mildew. (Mildew won't kill plants outright but will weaken them, resulting in less lavish flowering and fewer fruits.) Many gardeners feel that to avoid affecting the rest of the garden, it's best to remove struggling plants, especially in instances of pest infestation or wilt. "If it gets too aggressive or too wimpy, or gets mildew, just yank it," posted one gardener on a popular garden site. And don't fret. Removing unwanted plants will just open up a space to plant something new.


CLEAN IT UP!

Not only will your garden look a lot better if you do a little tidying, but you also may be able to encourage a whole new round of growth before summer's end.

Deadhead regularly. Removing old, spent flowers (called deadheading) can help keep plants blooming all season long. To spur growth further, the National Garden Association's Nardozzi suggests adding a shot of liquid fertilizer to your watering can before watering.
Give a good trim. Cut back reflowering plants like overly leggy petunias, geraniums, spiderwort, impatiens, phlox and bee balm. This tends to give them a second wind for another round of blooming.
Keep it neat. While it's not the time of year for major pruning, do prune any overly aggressive plants that are crowding out their neighbors. Your garden will look less cluttered and your plants will benefit from the additional growing space and breathing room. Don't neglect weeding and use twine and stakes to prop up plants that look precarious or have already fallen over.
Refresh mulch. Perk up your garden by raking off old mulch and replacing it with a 2- to 3-inch layer of fresh mulch or organic compost. Mulch not only improves the garden's appearance (bare dirt can be unsightly), but also helps inhibit weed growth and conserves water at the same time.

WATERING WISDOM

To beat the summer heat, more frequent watering is essential for keeping plants healthy, growing and looking good. If you're planning to be away over the weekend, check out self-watering containers, available at most garden centers; these containers have little reservoirs in the base. When the reservoir is filled with water, it naturally wicks up to the soil so your plants can drink up even when you're not at home! Consider adding water-absorbing polymers to your potting mix, suggests Nardozzi. Also available at local nurseries, these tiny crystals absorb water, expanding until they resemble small cubes of clear gelatin. As the soil dries, the water is released from the crystals, allowing the soil to stay moist.


RECYCLE CONTAINERS

Remember that plant containers can easily be reused from season to season. Charles Nardozzi suggests that when spring flowers start to droop, you remove and replace them with summer blooms like angel's trumpets (he recommends the new dwarf variety, which boasts fragrant yellow-peach flowers). Then, in the fall replace fading summer bloomers with cool-weather vegetables—spinach, lettuce, radish, broccoli or kale.