Answer: There are plenty of shrubs that bloom nicely in summer. There are dozens of options in hydrangeas. Weigelas have also maintained popularity; they bloom in early summer but will sometimes bloom again in late summer. Many mock oranges (Philadelphus spp.) bloom in summer, and they have the added benefit of great fragrance. In warm climates fuchsias grow as shrubs; some, such as F. magellanica can reach 10 feet tall. Here are a few shrubs with good summer flowers and small size.
Potentilla fruitcosa is a small round or spreading shrub, usually not much more than 3 feet, that blooms for a long period in summer. Cultivars are available with flowers in shades of yellow, red, pink and white. Grow the pale colors in full sun and the darker colors in part shade (harsh sun can bleach the petals). USDA Zones 2–7.
Rock roses (Cistus spp.) are also low shrubs. They bloom in shades of white or pink in early to midsummer and prefer full sun, good drainage and poor, rocky soil. (They’re Mediterranean plants.) Zones 8–10.
Several white-flowered hebes are prized for their evergreen foliage, but several also boast lovely summer flowers. Try Hebe ‘Emerald Gem’ (Zones 8–10) or H. rakaiensis (Zones 6–8), both compact shrubs with tiny green leaves and white flowers. ‘Spender’s Seedling’ and H. salicifolia (both Zones 7–9) bloom for a long period in summer. The latter can reach 6 feet. Hebes with more colorful, larger flowers in summer include ‘Blue Clouds’, ‘Marjorie’ and ‘Pink Paradise’ (all Zones 8–10).
Blue mist shrub (Caryopteris spp.) bloom from mid- to late summer into fall, with spikes of blue or purplish flowers on compact, usually 3- to 5-foot plants. ‘Dark Knight’ (Zones 5–9) offers the truest blue flowers.
Kolkwitzia amabilis ‘Pink Cloud’ (shown; Zones 4–8) bears pink flowers in profusion in early summer and will tolerate a range of soil types and some shade.
Want color year-round in your garden? This Month-by-Month Guide is full of shrubs and trees known for their excellent color.