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Late-Summer Flower Garden Renewal

Hibiscus 'Disco Belle Pink'
Hibiscus ‘Disco Belle Pink’ is a reliable late-summer bloomer.

In August, high summer is well established.  Drought and hot weather have generally taken their toll on gardens and gardeners, both of which may look and feel a little tired.  Caught between the tail end of the daylilies and the beginning of the asters, the holes in the borders begin to fill with crabgrass and other evil weedy entities.  We all want our plantings to look lovely, but when it is 95 degrees F in the shade the usual urge to dig in the dirt or refresh the containers is tempered by a natural reluctance to lift more than two fingers.

What to do?  A bit of inspiration won’t cool things off, but it may make the garden look better.  The following are a few easy-to-grow and easy-to-love plants that are in bloom now and can improve the look of late summer beds and pots.

Cheap Annuals

Petunia 'Madness Red' (MADNESS™ SERIES)
End-of-season petunias are cheap and will brighten up the late-season garden if given a little TLC. (Photo by Jessie Keith)

Most garden centers still have a few summer annuals left, generally lurking on the sale tables or grouped into mixed container arrays.  The garden centers want them out, and as long as the plants are still relatively pretty and healthy, you can use them to refresh your garden plantings.  A few of these plants will be goners, but many simply need liberation from the pots that have housed them since spring, a bit of pruning or pinching back, a judicious amount of liquid plant food, and a fair amount of water. Leggy petunias, sad impatiens, and seemingly spent snapdragons usually take to tender loving care and will respond by bouncing back and blooming nicely until frost.

Go to the garden center early in the morning, late in the afternoon, or on a cloudy day. Bring your bargain plants home, apply the restorative treatments right away, and pop them in place in the cool of the evening.  Don’t be afraid to disaggregate mixed containers and install the individual plants wherever you need them.  Mixed containers are all marriages of merchandising convenience anyway.

Now and Later Perennials

Coreopsis verticillata 'Golden Gain'
Tickseeds, such as the compact Coreopsis verticillata ‘Golden Gain’, will bloom towards season’s end with a little deadheading and care. (Photo by Jessie Keith)

When you take your cool-of-the-day trip to the garden center, keep an eye out for perennial species and varieties that are in bloom now.  Black-eyed Susans (Rudbeckia spp.) and their relatives, the ever-increasing coneflower clan (Echinacea spp.), are in bloom at nurseries all over the country and will multi-task when you get them home, supplying color now and the promise of the same thing next year at this time.  Their daisy-family kin, the tickseeds (Coreopsis spp.) are also in bloom and should produce at least one more flush before frost if you deadhead them at planting time. Look for reliable, tried-and-true varieties found at almost any nursery, such as the classic Coreopsis ‘Moonbeam’ with its vigorous habit and numerous pale-yellow flowers, and Echinacea purpurea ‘Magnus’ with its large pink flowers with dark cones.

Less formal perennials of late summer include Joe Pye-Weed (Eupatorium purpureum, 5-7′) a late summer star, especially for informal, cottage-type gardens or native borders.  This lofty perennial may not fit all garden sizes, so those with smaller borders may consider planting the somewhat shorter Joe Pye-weed, Eupatorium dubium ‘Little Joe’, which reaches only 3-4′ in height. All Joe Pye-weeds are stellar butterfly plants. Wand flowers (Gaura spp.) are also great late-summer butterfly plants that are airy, beautiful and generally drought tolerant.  The delicate variety ‘Pink Fountain’ is one of several pink-flowered forms that shine at this time of year. Use them in mid-border or medium-size pots for stature and delicacy.

Magnificent Mallows

Echinacea purpurea 'Pink Double Delight'
There are so many unique and pretty coneflowers for the garden, such as this Echinacea purpurea ‘Pink Double Delight’. (Photo by Jessie Keith)

Late summer is prime time for striking members of the mallow family, including shrubs like rose of Sharon (Hibiscus syriacus) and bodacious perennial bloomers like hardy, native, swamp mallow (Hibiscus moscheutos).  Both are widely available at nurseries and garden centers and bear large, prominent hollyhock-like flowers combined with attractive foliage.  Plugging a few mallows into a mostly fallow flower garden will add instant impact.  A container full of ‘Disco Belle Pink’ swamp mallow, with its enormous pink flowers, or large, red-flowered ‘Heartthrob’, will light up even the most uninspired space.
The large, bushy swamp mallow requires full to partial sun and can be grown either in-ground or in large containers.  If you try growing one in a container, start with a high-quality, moisture-retentive potting medium, like Fafard® Ultra Container Mix With Extended Feed.  Late summer mallows, especially the swamp type, are moisture lovers and the moisture-holding crystals in the Fafard mix will keep the plants happy, even during the inevitable dry spells.

Planting at the day’s coolest or cloudiest times will help new plants and heat-depleted gardeners stave off stress.  Be sure to water in plants as they are installed and the water daily, if necessary, until the weather starts to cool off.  After that, relax.  Your garden will have inspired the neighbors, even during summer’s dog days, and you will be ready to start thinking about all those bulbs that you ordered while sitting in front of the AC in August.

Read more summer gardening articles:
Protect Plants from Summer Heat
Pruning Summer Flowers

Beating The Five Most Common Vegetable Garden Pests Naturally

Jessie's daughter picking Colorado potato beetles
My daughter is picking Colorado potato beetles from potato plants.

For the past 11 years, I have grown my vegetables in a community garden plot, which has provided a rough, real education in plant pests, diseases, and weeds. Why? Because these mega veggie gardens are pest hot spots, and summer is the worst time of year for the beasties.  “Bad” insects always attack my beans, cucumbers, tomatoes, and eggplants–threatening to destroy fruits and foliage, and sometimes spreading disease as they munch and crunch along. I must use every tool in the toolbox to fight them. And, if the bugs beat my crop, I often start the crop again, if there is time and the season allows. Sometimes beating pests is just a matter of retooling planting time.

The five most common vegetable garden pests that I battle in mid to late summer are Colorado potato beetles, striped cucumber beetles, eggplant flea beetles, Mexican bean beetles, and harlequin cabbage bugs. Each return year after year with regularity, but some years are worse than others. The severity of the previous winter usually indicates the severity of my pest problems–the milder the winter, the harsher the pest problem. Last winter was pretty warm, so this summer the pests are rampant. Here are some ways that I have learned to overcome them.

Colorado Potato Beetle

Colorado potato beetles
Colorado potato beetles are mating on top of a potato plant.

The surest way to attract Colorado potato beetles to your garden is to plant potatoes, but if you don’t have potatoes, they will go for your tomatoes and eggplant secondarily. (Fortunately, they don’t appear to be attracted to tomatillos.) The fat, striped adult beetles emerge from the soil in late spring to feed on emerging potatoes and then lay clusters of orange-yellow eggs on leaf undersides. They yield highly destructive little orange larvae that eat foliage nonstop and grow quickly. You can kill the insects at any stage, but it’s easiest to pick off the adults and eggs. (Click here to view the full life cycle of these beetles.) The beetles can complete up to three life cycles in a single season, so once you have them, you generally have to fight them all summer.

Colorado potato beetle larvae on tomato
Colorado potato beetle larvae (left) on tomato.

These insects are highly resistant to insecticides, so it pays to choose non-chemical methods of control. Time and time again, well-timed cultural control, and proper winter cleanup have proven to be the best means of battling them. Cultural control is essentially picking off the adults, eggs, and larvae and/or pruning off egg- and larval-covered leaves and branches. I generally smash picked specimens, but you can also drown them in a bucket of water. Good picking should start in mid to late spring and continue until all signs of these pests are gone.
(To learn everything there is to know about Colorado Potato Beetles, visit potatobeetle.org.)

Spotted and Striped Cucumber Beetles

Symptoms of bacterial wilt
The symptoms of bacterial wilt, which is spread by the striped cucumber beetles.

As their names suggest, striped and spotted cucumber beetles favor cucumbers, but they also attack melon vines. Small, striped or spotted cucumber beetles look so cute and innocent, but they are so destructive. Every year my cucumber crop is a crapshoot. Why? It’s not because of the damage they cause by feeding on plants and fruits. It’s the catastrophic bacterial wilt that they spread from plant to plant. Once cucumber vines get cucumber bacterial wilt, there is no turning back. The leaves will start to show droop, and eventually, whole stems will collapse, and the vine will die.

Yellow beetle

These pests may have two to three cycles in a season and are next to impossible to control, even with harsh chemical insecticides. Floating row cloth cover can keep them at bay, but it is a hassle and does not allow pollinators to reach the plants. For me, the best course of action is to choose bacterial-wilt-resistant cucumber varieties. Cornell University Extension offers a great list of resistant cucumber varieties from which to choose. Of these, I have grown the short-vined slicer ‘Salad Bush,’ which is great for container growing. Two more reliable varieties are ‘Marketmore 80‘ and ‘Dasher II.'(Click here to learn more about striped cucumber beetles.)

Eggplant Flea Beetle

Eggplant flea beetle damage on eggplant leaf
Eggplant flea beetle damage on an eggplant leaf.

Tiny jet-black eggplant flea beetles are the smallest summer pests in this list, but they can devastate an eggplant in a matter of days. The small but numerous insects leave little pockmarks all over a host plant’s leaves. Badly damaged leaves barely photosynthesize, resulting in poor, weak plants that produce puny fruits.

If you want to grow eggplant, you have to protect them from eggplant flea beetles. There are plenty of insecticides that will kill these insects, but only a few non-chemical cultural practices will stop them. The best method that I have found is protecting plants with summer weight floating row covers that transmit a lot of sunlight while physically keeping insects from the plants. The key is covering plants early and then securing the row covers at the base, so the tiny beetles cannot crawl beneath them. Holding cover edges down with bricks, pins, and even mulch or compost works. The only caveat is that you may need to hand-pollinate plants for fruit set.

Good fall cleanup of infested crop plants will also keep populations down from year to year. On average, eggplant flea beetles will complete up to four generations in a single season.
(Click here to learn more about these pests.)

Harlequin Cabbage Bug

Harlequin adult bugs on summer broccoli
Harlequin bug adults do damage to summer broccoli.

These ornamental stink bugs are the worst enemy of summer kale, broccoli, and other brassicas. They suck the juices from the leaves, causing pockmarks all over them. The most striking destruction I have ever witnessed was with enormous Portuguese kale that I had nurtured to a bold 2′ height through spring. Once the numerous beetles started to attack in early summer, the plant had no chance.

There are a few management practices that will help stop these bugs. Floating row covers can also be used, as was suggested for the eggplant flea beetles, but harlequin cabbage bugs are big enough to pick off by hand if you have the time and can handle the slightly stinky smell they emit when disturbed. Small nymphs are also susceptible to treatment with OMRI Listed® insecticidal soap.

Two to three generations of harlequin cabbage bugs can occur each season. By late summer, they are no longer a problem so that you can plant your fall cabbages and kales with confidence.
(Click here to learn more about these pests.)

Mexican Bean Beetle

Mexican bean beetle larvae on bean leaf
Mexican bean beetle larvae and their damage on a bean leaf.

Like Colorado potato beetles, it’s the larvae of Mexican bean beetles that do the harshest damage to bean plants. The adults emerge in late spring, but they rarely cause major problems on bean plants until midsummer. The adults are orange, black-spotted beetles that lay clusters of orange-yellow eggs below the leaves, much like the Colorado potato beetle. The unusual larvae are fuzzy, bright yellow, and devastate leaves as they feed along the leaf bottoms.

Beetle on damaged leaf

Tou can control these pests as you would Colorado potato beetles with one exception – destructive harvesting. Destructive harvesting is the harvest and total removal of infested plants from the garden. After picking, infested plants should be pulled, bagged, and taken far from your garden. (Click here to view a YouTube video from the University of Maryland about destructive harvesting.) Beans can be replanted as late as mid-August for early fall harvest.

In general, regular weeding, good plant care, and excellent garden clean up, in summer and fall, will help keep pest populations down. Clean the ground of all leaf litter and weeds, and amend the soil with top-quality amendments for vegetables, such as Fafard® Garden Manure Blend or Natural & Organic Compost, and your plants will be more robust to resist the many garden pests that threaten to destroy them.