When it’s hot and humid outside, wouldn’t you rather be inside enjoying a glass of iced tea? You bet. But wait! Summer may be uncomfortable for us but it’s a great season for colorful flowers in your perennial garden. So grab that iced tea and brave the heat for a few simple chores. The payoff will be a garden full of flowers. Here’s what to do:
Deadhead perennials for more blooms
Deeply soak perennials with water in summer
This is the time of year most gardens need extra water. A long deep soaking is better for plants than short daily drinks. The exception is containers. Those plants have grown a lot of roots so when it’s really hot, daily watering is a must.
Stop fertilizing perennials in late summer
Don’t feed perennials or shrubs, especially roses, after mid-August so plants can start going dormant for winter. You don’t want tender new growth to be killed by cold. Annuals won’t make it anyway, so continue to feed them through fall. Now, check out these two great summer combos you can grow!
Cool-colored summer perennials
Royal purple paired with pale yellow and silver strike just the right note in this beautiful sunny border. And a variety of flower shapes keeps it interesting. Contrasting foliage shapes, such as the spiky iris and fuzzy lamb’s ear, will be a pleasure to look at even when the flowers aren’t blooming.
A) Daylily (Hemerocallis ‘Happy Returns’)
Type Perennial Blooms Lemon-yellow flowers spring to fall Light Full sun to part shade Size 12 to 18 in. tall and wide Hardiness Cold hardy in USDA zones 3 to 9
B) Salvia (Salvia nemorosa ‘Caradonna’)
Type Perennial Blooms Purple flowers with deep purple stems summer to fall Light Full sun Size 18 to 20 in. tall, 12 to 18 in. wide Hardiness Cold hardy in USDA zones 4 to 9
C) Lamb’s ear (Stachys byzantina)
Type Perennial Blooms Lavender flower spikes in spring Light Full sun Size 8 to 12 in. tall, 12 to 18 in. wide Hardiness Cold hardy in USDA zones 4 to 8
D) Catmint (Nepeta sibirica ‘Souvenir d’André Chaudron’)
Type Perennial Blooms Lavender flowers spring to summer Light Full sun Size 24 to 36 in. tall, 12 to 18 in. wide Hardiness Cold hardy in USDA zones 3 to 8
E) Sweet iris (Iris pallida pallida)
Type Rhizome Blooms Fragrant purple flowers in spring Light Full sun Size 18 to 24 in. tall, 15 to 18 in. wide Hardiness Cold hardy in USDA zones 4 to 9
F) Lady’s mantle (Alchemilla mollis)
Type Perennial Blooms Long-lasting chartreuse flowers in early summer Light Full sun to part shade Size 10 to 18 in. tall, 18 to 30 in. wide Hardiness Cold hardy in USDA zones 4 to 8
Need more inspiration? Check out our Garden Design Plans
Iris flowers best if you divide it every 3 to 4 years. It’s easy to do in late summer. Dig the clump out of the ground, break off the rhizomes with foliage and discard the others. Replant at the same depth the rhizomes were already growing and water them in.
Bright summer perennials to up the energy
You can’t miss by combining the three primary colors of red, yellow and blue. Vibrant reds and sunny yellows are exciting colors but might be a little over the top if it weren’t for the soft blue-purple to tone them down in this full-sun combo.
A) Heliopsis (Heliopsis helianthoides scabra ‘Summer Sun’ (‘Sommersonne’))
Type Perennial Blooms Single to double yellow flowers in summer Light Full sun Size 24 to 36 in. tall, 18 to 24 in. wide Hardiness Cold hardy in USDA zones 3 to 9
B) Balloon flower (Platycodon grandiflorus)
Type Perennial Blooms Blue-purple flowers in summer Light Full sun Size 12 to 30 in. tall, 12 to 18 in. wide; cold zones 3 to 9
C) Bee balm (Monarda ‘Jacob Cline’)
Type Perennial Blooms Red flowers in summer Light Full sun to part shade Size 36 to 48 in. tall, 24 to 36 in. wide Hardiness Cold hardy in USDA zones 4 to 9
See our Flower & Plant Guide
If you need something smaller, try yellow ‘Double Cutie’ daylily (Hemerocallis hybrid), blue ‘Vision Violet’ geranium (Geranium sanguineum) and red ‘Fireball’ bee balm (Monarda hybrid). All stay under 2 ft. tall.