This is an article about five of my favorite late summer perennials, you know, the colorful kind that can endure and thrive during the hottest time of year. My preference is for perennial plants that are easy to care for and are at their best when the weather is hot and humid.

What time of year are we aiming to tame? You know it as the dog days of summer, but it might be more appropriate to call it the sloth days. It’s when humans slow down but gardens don’t. Things outside get downright jungle-like. It’s so hot you’ve taken to inspecting your garden with binoculars from the air-conditioned comfort of your kitchen. A mob of mosquitoes has just carried off your neighbor’s cat, and the weeds have staged a coup on your once-promising vegetable garden.

August through early September offers a mixed bag of heat, drought, downpours, and gale-force winds. It’s the time that is toughest on gardens as well as on gardeners. Annuals and tropical plants make colorful additions, but of course, variety is key to any garden. Let’s plant some perennials that look great during the dog days, and while you are at it, attract butterflies, bees and even hummingbirds.

Here are five of my favorite perennials that look fresh in the midst of whatever the summer dishes out.

Candy lily (Pardancanda norrisii)

Not a lily at all, but a member of the iris family, this is truly a designer late summer perennial. Its botanical name, Pardancanda, is a combination of its original parent plants: Belamcandaand Pardanthopsis. The plants were hybridized in 1967; crossing the red and yellow-flowered Belamcandawith the purple flowers of Pardanthopsis. Each flower on the candy lily blooms for only one day, but each stem has dozens of flowers. After blooming, petals of the flowers look like twisted candy wrappers.

Plants can grow to a height two feet to over four feet, with flower colors that range from orange and yellow to shades of pink, white or purple. Petals can be speckled, spotted, blotched, or unmarked. A new variety called ‘Soft Spot’ has blue flowers and reaches 33-inches tall, while the Dazzler series of candy lily reaches just 18”.

GROWING TIPS: you get a lot for your money when you buy candy lily. To keep it happy, it’s good to divide plants every other spring. They don’t miss a beat, though, and will bloom the same year they’re divided.

Pardancanda     Photo: Jean Starr

Phlox (Phlox paniculataor tall garden Phlox)

Don’t discount Phlox as a “grandma” plant that comes down with terrible mildew in late summer. There are so many mildew-resistant varieties to choose from, you will have trouble deciding which ones to grow. One new variety that holds onto its blooms the longest is ‘Maiden America’, a two-footer that comes into bloom in mid-July and stays that way for a month. Check out Perennial Pleasures Nurseryin East Hardwick, Vermont, an online and on-site nursery that specializes in Phlox.

According to When Perennials Bloomby Tomasz Anisko, some of the varieties that bloom late in the season include ‘David’, ‘Eva Cullum’, and ‘Norah Leigh’. Whether you want blooms in early July or late August, it’s a good idea to cut the plant back by a third some time in early June. This encourages branching, which means the plant will have more flowers.

GROWING TIPS: Mildew resistance doesn’t mean mildew-proof, so good cultural practices are a good idea no matter what varieties are used. Give the plant good air circulation, and be prepared to supplement its moisture at the root zone, not the leaves. In the spring, remove all but about five strong stems at ground level.

Phlox     Photo: Jean Starr

Helenium

Unfairly referred to as “sneezeweed,” Heleniumgets a head start on autumn russets and golds, typically beginning its bloom in mid-August. The plants have daisy-like flowers with adorable raised button centers. Thanks to hybridization, plants can be found from two feet to five feet tall, with shorter varieties tending to bloom earlier in the season. Warm climates and rich soil could contribute to the taller varieties flopping, so those over three feet tall might need to be staked.

For those with smaller gardens, the Mariachi Series of Helenium is ideal. Varieties in this dwarf group go by names that include Helenium ‘Salsa’, ‘Bandera’, ‘Fuego’, and ‘Siesta’. Both ‘Carnival’ and ‘The Bishop’ stage an in-between show at just three feet tall.

GROWING TIPS: Helenium is prone to a bit of mildew on its lower stems. Cover them up by planting something shorter in front of it to hide the bare stems.

Helenium     Photo: Jean Starr

Rose mallow (Hibiscus moscheutos)

This hardy hibiscus looks more like its exotic cousin, with its huge, bright flowers. But rose mallow is not only hardy to Zone 5, it is an American native. Newer hybrids are compact, usually growing no more than three feet tall by four feet wide; and have more flowers than the older varieties. New introductions began to hit the garden centers right after the turn of the century. These have included larger, thicker, ruffled and bi-colored flowers on stems more substantial, with better branching and darker leaves.

Hibiscus SUMMERIFIC ‘Perfect Storm’ came on the scene in 2016, a more compact version of a previous variety called ‘Summer Storm’. The latest introduction by Proven Winners is SUMMERIFIC ‘Holy Grail’, boasting the best combination of all–deep red flowers, compact size and mahogany leaves.

GROWING TIPS: According to Walters Gardens, keeping Hibiscus hybrids watered will result in larger flowers and lush foliage. Deadheading will improve the appearance of the plant. Hibiscus is always one of the last late summer perennials to emerge in spring, so don’t assume you’ve lost it and dig it up.

Hibiscus     Photo: Jean Starr

Butterfly bush

Buddleia(pronounced BUD-lee-uh) is in the category called a subshrub, because, although it has the appearance of a shrub, in areas with very cold winters, it dies back to the ground and sprouts again in the spring. New hybrids have been bred for smaller size, bigger flowers and sturdier stems.

The Lo & Behold series by Proven Winners features a variety of very hardy plants that reach less than two feet tall, making them perfect to plant on a slope or at the feet of a tall hummingbird and butterfly magnet like Salvia ‘Amistad’. One of my favorites has been Buddleia Monarch ‘Prince Charming’, its bright pink color unusual in Buddleia.

GROWING TIPS: Leave the stems on the plant through the winter and wait until you see new growth from below ground before pruning them off. In years with mild winters, Buddleia can sprout from the previous season’s stems. However, it’s best to prune it back to encourage a bushier plant and more blooms.

Buddleia     Photo: Walters Gardens

 Final Thoughts on Favorite Late Summer Perennials

All these perennials will return with little encouragement. Most prefer to be planted in the spring, when the temperatures are cooler and they can become established well before their performance is scheduled. Think ahead when you buy your plants in the spring, or visit garden centers in late summer to find some of these plants in pots and ready to plant.