Planting a few fast-growing shrubs is just the ticket to cool down a sun-drenched spot in the yard or on the patio. Besides providing shade, plants release cooling water vapor through transpiration, so they consistently add moisture to the air, driven by sun and heat. Plants with dense foliage or large leaves tend to give off the most moisture.

When choosing shade shrubs for the garden, be sure to add the colors green, blue, and violet, which are considered cooling, calming colors for the garden. Shrubs with yellow foliage and red or orange flowers may increase the hot vibe, so stick to shrubs with shades of green, blue, and violet.

Summer Planting Requires Extra Care

Nursery container-grown shrubs can be planted during the summer, but you should take extra precautions. Plant when the sky is overcast or during the early evening when it is cooler, then water deeply. Also, keep the plant well watered until it is established. You may need to water daily if it is hot enough or every other day. This deep root watering tool from Amazon is really useful for helping trees and shrubs to establish and develop a strong, deep root system.

However, avoid fertilizing in the heat of summer. Adding 2 to 3 inches (5 to 8 cm) of mulch will keep the roots cool and moist. Place the mulch at least 4 inches from the base of the shrub.

Fast-Growing Shrubs for Cooling Shade

Whether you design a private reading nook surrounded by shrubs or a mixed border along a hot, western exposure, here are fast-growing shrubs that will put you in the cooling zone. Be sure to read the plant tags and choose shrubs suitable for your USDA hardiness zone.

1. Viburnum

Viburnums (Viburnum spp.) include deciduous and evergreen shrubs in varying heights that include some North American natives. They feature flowers, mostly white, as well as colorful fall leaves. Some varieties also produce fruit in the fall, which is relished by birds. Viburnums grow 1 to 2 feet (0.3 to 0.6 m) a year. Depending on the variety, viburnums prefer full sun to light shade and well-draining soil. Add organic matter to the soil when planting to increase fertility and drainage.

Good ones to try include Arrowwood (V. dentatum), which grows 6 to 12 feet tall and wide (1.8 to 3.7 m) in USDA zones 3 to 8, and produces blue-black fruit. American cranberrybush (Viburnum opulus var. americanum) grows 5 to 8 feet in zones 2 to 7, and produces red fruit in late summer. Leatherleaf viburnum (V. rhytidophyllum) is evergreen to semi-evergreen with white flowers in spring and red to black berries in fall. It grows 10 feet (3 m) tall and wide in zones 5 to 8.

2. Ninebark

Ninebark (Physocarpus opulifolius) is a tough, drought-tolerant Eastern North American native shrub that grows up to 8 feet (2.4 m) tall in zones 2 to 8. It is known for its exfoliating bark, which shows in winter after the leaves drop.

Several cultivars are offered with foliage colors such as purple, yellow, chartreuse, and bicolor. ‘Diabolo’ ninebark features purple foliage and creamy white flowers in summer. ‘Snowfall’ sports dark green foliage and white or pink flowers.

Ninebark does well in slightly acidic, well-drained soil in full to part sun. It tolerates multiple soil conditions, including clay.

3. Panicle Hydrangea

Panicle hydrangeas (H. paniculata) bloom from midsummer to fall on new growth, so you don’t have to worry about late freezes zapping the flower buds. Their strong stems support conical-shaped flower clusters, typically white, changing to pink or red.

Panicle hydrangeas tolerate more sun than other types of hydrangeas but still prefer morning sun and afternoon shade in well-draining soil in zones 3 to 8.

Their height depends on the cultivar, but to provide more shade, choose the taller varieties like ‘Quick Fire,’ ‘Pinky Winky,’ ‘Limelight,’ ‘Vanilla Strawberry,’ and ‘Fire Light,’ which grow to 8 feet (2.4 m) tall and wide. ‘Phantom’ hydrangea features huge white flower heads and quickly grows up to 10 feet (3 m) tall and wide.

4. Rose of Sharon

Rose of Sharon (Hibiscus syriacus) grows quickly into a vase shape from 8 to 12 feet tall (2.4 to 3.7 m). The hibiscus-like flowers bloom non-stop from summer to fall and attract pollinators. Flower colors in pink, red, blue, white, purple, violet, and bicolor are available in single and double types.

Older varieties tend to reseed easily, but many new cultivars are sterile, eliminating that problem. Look for ‘Diana,’ ‘Aphrodite,’ ‘Azurri Blue Satin,’ ‘Orchid Satin,’ ‘Helene,’ and the ‘Sugar Tip’ series.

Rose of Sharon prefers full sun and tolerates heat, humidity, and drought in zones 5 to 8.

5. Dappled Willow

Dappled willow (Salix integra 'Hakuro-Nishiki') trees are coveted for their pretty variegated foliage that flows like a fountain. Their multicolored leaves are a striking pink, white, and apple green. Hardy in zones 4 to 10, they grow almost anywhere.

Dappled willow prefers a moist, fertile soil in full to part sun. It grows 8 to 10 feet (2.4 to 3 m) tall and wide. Pruning the foliage a couple of times a season brings a flush of new foliage. Catkins produced in spring persist into fall.

6. Crape Myrtle

Fast-growing crepe myrtle (Lagerstroemia indica) trees can reach their height in one season! The heat-loving shrub blooms from midsummer to fall in showy shades of red, pink, white, lavender, and purple ruffled flowers. When autumn arrives, leaves change to yellow, orange, or red.

Crepe myrtle grows from 6 to 30 feet (1.8 to 9 m) tall depending on the variety, in zones 6 to 9. If the top growth dies back during an extreme winter, it will grow back from the roots. Exfoliating bark adds winter interest.

Adding fast-growing shrubs to your landscape will soften the edges, bring soothing green colors, and actually reduce the ambient temperature through leaf transpiration, especially if the shrubs are grouped together.