Summer Garden Color

Cultivating color and bloom in the summer garden can be difficult but there are some award winning trees and shrubs that shine in the summer. We joined Bob Aube, co-owner of Morningstar Nursery in West Kingston, for the second of a two part series to look at trees and shrubs that bring interest to the summer landscape.

Stewartia

Stewartias are beautiful trees. There are a number of different varieties to choose from, but all of them have something to offer during every season of the year. Depending on the variety, they can reach as high as 45 feet, but they are slow growing and will take decades to reach that height. Stewartia trees generally grow in a narrow vase shape, reaching 15 feet wide at the top and considerably narrower at the bottom. Stewartia blooms in June, when few other trees are in bloom. The attractive white flowers usually have yellow stamens and resemble camellia blossoms. The leaves color up spectacularly in the fall, usually turning a stunning red before falling from the tree. Another benefit of Stewartia is that it is attractive even without the leaves in winter. Stewartia's have attractive exfoliating bark that reveals pretty patches and patterns of color where the bark has peeled off. There are several varieties to choose from. The Japanese Stewartia (S. psuedocamelia) is one of my favorites. It's the biggest variety, eventually reaching 45 feet. Another favorite is S. malacodendron with white flowers with purple stamens (only reaches about 15 feet). Stewartia trees are generally pest free, incredibly attractive trees. Give them a try; you'll be glad you did.

Dappled Willow Salix integra 'Hakuro Nishiki'

This is a small tree or large shrub (3-5 feet in height) suitable for most gardens, provided they receive fairly plentiful sun. Elegant, with long, slightly drooping branches when it reaches maturity, in its earlier years Salix integra 'Hakuro nishiki' is enjoyably boisterous.The young branches develop in all directions, creating a starburst of color and interest. Eventually they start to bend downwards under their own weight. Visual benefits at other times of the year include delicate catkins along the stems from early April, quickly followed by pairs of attractively marked, oblong, bright green leaves. Although willows are often associated with waterside situations, 'Hakuro-nishiki' will also thrive on drier soils.

Potentilla - Shrubby Cinquefoil

Potentillas prefer well-drained, reasonably rich soil, but will tolerate clay, rocky, or slightly alkaline soils as well. They are a quite durable plant, tolerating drought, flooding, extreme cold, and will easily survive transplanting. Potentillas should be planted in a sunny area that receives light shade in the hottest part of the day to prevent the flower color from fading. They are hardy in areas as cold as USDA zone 2, however they will not perform very well in climates warmer than zone 7. Propagation can be accomplished by division in the spring, softwood cuttings in the summer, or from seeds sown in the fall. Prune out the oldest stems in late winter to prevent the plant from becoming leggy.

Hydrangea macrophylla

Hydrangeas are one of the most popular flowering shrubs in southern New England. Gardeners prize hydrangeas for their vibrant flowers that add drama to the summer and fall garden. Hydrangeas also thrive in our maritime climate, particularly along the coast where the temperature is mild. The most commonly planted hydrangeas are varieties of Hydrangea macrophylla including the popular blue-flowered varieties such as Niko blue. However there are literally hundreds of other varieties to try. Hydrangea macrophyllas thrive in a location where they will receive morning sun and afternoon shade; the shrub is vulnerable to wilting when planted in full sun. Also, Hydrangea macrophylla may not be a good choice if you live in a colder region, such as the northwest corner of Rhode Island. The plant forms its flower buds on last season's growth. This means that the flower buds must overwinter and thus are more vulnerable to cold damage. Other species of hydrangea flower on the current year's growth and are more cold tolerant. See Plant Pro tips on cold hardy hydrangeas for more information.

For a details on hydrangea varieties and care, including the relationship between soil pH and flower color, see our fact sheet at: Hydrangea

For more information on starting a Container Garden, visit the URI CE web site: www.uri.edu/ce/ceec or call the URI Master Gardening Hotline: 1-800-448-1011.

Written by James Proctor