Southwest

I once heard a local plantswoman moan, “I am so over Russian sage. It’s a weed here.” It’s not exactly a weed, but Russian sage (Perovskia atriplicifolia, Zones 4 to 9) spreads like crazy and is difficult to eradicate once planted. The more compact version, ‘Filigran’ (Zones 5 to 9), doesn’t sprawl and looks better in garden borders. Hollyhocks (Alcea, Zones 3 to 9) can also be bullies in the high desert, seeding themselves in places where you don’t really want 6-foot-tall plants. Instead, try hollyhock mallow (Malva alcea, Zones 4 to 9), a 4-foot-tall beauty that knows how to behave. Last year, when sunflowers (Helianthus spp.) took over one of my gardens, I vowed to get my yellow fix from Coreopsis grandiflora (Zones 3 to 9) and Gaillardia x grandiflora ‘Arizona Sun’ (Zones 3 to 9). They’re just as brilliant in late summer, but won’t turn your backyard into a sticky-stemmed jungle. —Stephanie Hainsfurther, Albuquerque, NM

Tips
• All of these plants like full sun and well-drained soil.
• The blooms of hollyhock mallow tend to be brighter with a little protection from the desert sun.
• If you’re tired of yellow-and-orange flowers, try Gaillardia ‘Burgunder’ (also sold as ‘Burgundy’), which has wine-red blooms.

What to do this season
• Step up watering and feeding to keep late-summer bloomers happy until they can put on a show.
• Soak containers to flush out salts.

Northeast

Years ago, when many of my friends were getting married, I did a lot of flower arranging. For large arrangements I’d often start with some sort of shrubby material, and false spirea (Sorbaria sorbifolia, Zones 2 to 8) worked perfectly. It has plentiful, disease-free foliage; its fragrant, frothy, white flowers are similar to those of astilbe; and it blooms in late June, just in time for wedding season. It took me about two years to realize why this shrub isn’t more popular, and about four more years to eradicate its fleshy roots, which roamed 6 feet in every direction. Goat’s beard (Aruncus dioicus, Zones 4 to 7) is a well-mannered alternative. It’s a perennial, rather than a shrub, and has deep green foliage and wands of delicate white flowers in mid-June.
—Katherine LaLiberte, Richmond, VT

Tips
• Goat’s beard is a North American native that’s well suited to woodland plantings or the back of a shade garden. It tolerates full sun, but looks best in part shade. It grows 4 feet tall and wide. Needs moist to wet soil.
• Good companions for goat’s beard include hosta, astilbe, bleeding heart, lungwort, and coral bells.

What to do this season
• Some early-summer perennials will bloom a second time if they’re trimmed after they flower. Good candidates for this treatment include cranesbill geraniums, threadleaf coreopsis, and catmint. Shear plants as soon as they’ve passed peak bloom and before they set seed.

Pacific northwest

We think of English Holly (Ilex aquifolium, Zones 7 to 9) as the ultimate Christmas decoration. As a garden plant, however, this dense 30-foot-tall evergreen tree causes problems. Bird-deposited seeds have helped English holly naturalize in the Pacific Northwest. Because it can grow in sun or shade, it displaces native plants in several habitats. Holly-leaved osmanthus or false holly (Osmanthus heterophyllus, Zones 6 to 9) is an evergreen shrub that grows 10 feet tall and offers many of English holly’s good qualities without being a pest. Its branches are just as lovely in holiday arrangements and it grows well in a pot or in the garden. Several cultivars are available: ‘Purpureus’ has dark stems, ‘Variegatus’ has a white leaf border, and ‘Goshiki’ has cream and bronze splashes on the foliage.
—Marty Wingate, Seattle, WA

Tips
• Grow Osmanthus heterophyllus in sun or part shade.
• Once false holly is established, it won’t need supplemental water.
• To prune false holly, take out one tall branch at a time. After cutting back each branch to where it attaches to a bigger stem, step back to see if it needs more pruning. 

What to do this season
• Set out transplants for the winter vegetable garden—purple-sprouted broccoli, cauliflower, and cabbage.
• Deadhead late-summer perennials.
• Sit with a glass of lemonade in a comfy chair under the shade of a tree and enjoy the garden!

Midwest/mountain

Japanese honeysuckle (Lonicera japonica) is a terribly invasive vine with fragrant, white to pink tubular flowers that turn yellow with age. This vine spreads rampantly, and its dense growth usually kills the plants it climbs on. A much better-behaved cousin is our native scarlet honeysuckle (Lonicera sempervirens, Zones 4 to 8), which grows 10 to 12 feet tall. The blue-green foliage complements prolific clusters of tubular red flowers with yellow throats in May and June. The flowers are followed by red berries in summer and fall. Hummingbirds visit the flowers for nectar and birds eat the berries in the fall. ‘John Clayton’ is a nice cultivar with pale yellow flowers from June through November. —Natalia Hamill, Lawrence, KS

Tips
• Scarlet honeysuckle will grow in shade, but it needs sun to flower well.
• Plant in well-drained sandy or
loamy soil.
• Grow on a trellis, arbor, or fence so the twining stems have something to wrap around.
• The vine generally blooms on the previous year’s stems, so prune to shape after flowering.

What to do this season
• Divide and replant crowded iris.
• Keep mulch on your beds to reduce weeds and conserve soil moisture.
• Plant a fall vegetable garden.

Southeast

Evergreen foliage, spring flowers, and bunches of black berries helped Chinese privet (Ligustrum sinense) win places in 19th-century Southern gardens. But as birds spread the seeds, privet displaced woodland plants and became a landscape nuisance. Help stop this thug by removing it and filling its niche with something better. My top choice is wax myrtle (Morella cerifera, often listed as Myrica cerifera, Zones 7 to 10), a native shrub that serves as a host plant for butterflies and is a great food plant for birds. Wispy wax myrtle leaves release a bayberry fragrance when crushed, and the waxy coating on the berries is scented, too. Sometimes called Southern bayberry, this nitrogen-fixing shrub will grow in sun or part shade, and thrives with little care. —Barbara Pleasant, Pisgah Forest, NC

Tips
• The species grows 15 feet tall, but compact cultivars such as 6-foot-tall ‘Don’s Dwarf’ are easier to fit into small spaces.
• You can prune wax myrtle into
a hedge or sculpt plants into an elegant upright shape.
• Remove the lowest branches from
a mature wax myrtle to improve your view of its multiple trunks.

What to do this season
• Deadhead long-blooming annuals such as salvias and zinnias, and trim back basil and other herbs.
• Reduce the risk of black blemishes on the blossom ends of your tomatoes by thinning fruits to three
per cluster and keeping the soil lightly moist at all times.