Hydrangeas, Crape Myrtles and Giant Himalayan Lilies: Summer Delights at the Botanic Gardens

Summer is a great time to visit the UW Botanic Gardens and offers the best weather of the year to enjoy blooms and botanically interesting walks.

Lacecap Hydrangea
Stephanie Jeter
Hydrangea macrophylla ‘Lanarth White’ and ‘Hamburg’ at the Washington Park Arboretum.

In the Arboretum, early summer hydrangeas are at their peak in late June and early July.  Find many varieties in the Camellia Family collection area and the Woodland Garden.  The Arboretum features many old-fashioned varieties of Hydrangea macrophylla (both mophead and lacecap types) and Hydrangea serrata (the mountain hydrangea of Japan).  We also have many other species from Asia and eastern North America, including some that reach the size of small trees as well as climbing species.  The giant leaves and large lacecap-type blooms of Hydrangea aspera are found in several places throughout the Arboretum.

Early summer also features Styrax (snowbell trees), Philadelphus (mock oranges) and Deutzia through early July.

Cindy Clark
Stewartia flower

The start of summer showcases the white camellia-like blooms of Stewartia species, part of the Camellia Family and prominently featured in that part of the Arboretum.   Stewartia serrata starts the show, followed by Stewartia pseudocamellia and Stewartia monadelpha.  The latter two are truly four-season trees, with spectacular bark year round and outstanding fall color.  July and August are when Stewartia ovata (mountain camellia) and Stewartia malacodendron come into bloom.  The Arboretum has one of the best collections of these trees in the United States.

Stephanie Jeter
Magnolia grandiflora ‘Goliath’

Magnolia virginiana (sweet bay) is at its best in late June, with fragrant flowers continuing through July.  July also begins the season of bloom for the Magnolia grandiflora (evergreen magnolia).  This large glossy leaves set off the large, creamy-white flowers and their citrus-sweet fragrance.  Blooms continue throughout the summer.

In the Pacific Connections Gardens, look for the giant Himalayan lily (Cardiocrinum giganteum) in late June in the China Entry Garden.   Red and yellow blooms of hardy ginger relative Cautleya spicata follow in July.  Hardy fuchsias (Fuchsia magellanica and cultivars) take center stage in the Chilean Entry Garden, blooming from June to frost.

S. McGuire
Cardiocrinum giganteum in the China Preview Garden

In the New Zealand Forest, Olearia species (tree daisies) bloom in July, followed by the flowers of sweeps of ornamental grasses (Chionochloa species) contrasting with the fine-textured broadleaved evergreens.  Veronica (Hebe) species bloom sporadically throughout the summer.

In the Legume section, Maackia chinensis and Maackia amurensis trees bloom with white, pea-like flowers in July.

Coming into August, look for blooms of the Sourwood tree, Oxydendrum arboreum in the Woodland Garden.  These rhododendron relatives have white pendant flowers that bloom atop the shiny green leaves at the tops of these small trees.

In August, Eucryphia species feature fragrant 1-2” wide, white and yellow flowers.  Find these at the northeast part of Rhododendron Glen near Arboretum Drive, and in the Chilean and Australian Entry Gardens.

S. McGuire
Crape myrtles (Lagerstroemia) thrive in the reflected heat of a parking lot at the Center for Urban Horticulture.

September highlights include late-blooming crape myrtles (Lagerstroemia) along the north part of Azalea Way.  The golden rain tree, Koelreuteria paniculata, continues its ornamental show of bright yellow July flowers with a September covering of balloon-like, pale green and brown fruit capsules at the Duck Bay parking lot.  Our extensive Oak Collection, one of the best in North America, provides shade on those warm summer days.  Fall color starts to peek through in the Woodland Garden by the end of summer.

At our Center for Urban Horticulture location across Union Bay, the Orin and Althea Soest Herbacious Display Garden dazzles with a succession of blooms throughout the summer.  In August and September, crape myrtles (Lagerstroemia species and cultivars) bloom in Seattle’s best display of these small trees with attractive, mottled bark.  It is also the perfect time to enjoy the trails of the Union Bay Natural Area.

Summer is the best time to enjoy the outdoors in Seattle, and the UW Botanic Gardens are the perfect place to explore the beauty of plants and nature in the middle of the city.