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Summer Splendor

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Oh, my aching muscles...

Flowering Trees and Shrubs

By Sean Hogan

As summer comes on in the Northwest, our soft winter greens turn hard and baked. In the southern parts of our region, especially in the Willamette Valley, we are surrounded with great expanses of gold. At a time when the garden naturally shuts down, plenty of woody plants reach their peak. These beauties perform when the weather is at its hottest—some even without the addition of water.

Trees

First on my list—planted long ago in the Northwest and just now regaining popularity—are the eucryphias. These southern hemisphere beauties from both Chile and southeastern Australia are mostly evergreen and vary in size and shape from shrubs to trees. Eucryphia milliganii, only about four or five feet in height after many years, has glossy leaves and, in June and July, abundant half-inch white flowers with a boss of black tipped stamens. Larger and indeed more tree-like, reaching to 10 feet or more and narrow in shape, E. glutinosa has large flowers also in midsummer. The earliest of the genus to have been used in our part of the world, it is also the only deciduous species.

Eucryphia x nymansensis, an old hybrid of E. glutinosa and E. Cordifolia is again taller, reaching a narrow 15–20 feet. Eucryphia x nymansensis ‘Mt. Usher’ is a particularly lovely cultivar. Another hybrid, E. x intermedia ‘Rostrevor’ (E. glutinosa x E. lucida) is similar but somewhat smaller in stature with more clustered flowers. Eucryphia lucida is still taller, to an eventual 20 feet with a narrow form, shiny, rounded, two-inch leaves, and abundant, midsummer flowers. It is one of the more tender of the bunch (to about 10 to 12 F). This favorite of mine has produced some of the most desirable garden variants, including E. lucida ‘Pink Cloud’ with pearly pink flowers —just as the name would imply.

The variegated E. lucida ‘Leatherwood Cream’ with cream-streaked foliage becoming rosy in winter is especially striking during the hottest weather, sporting starched white flowers. All need sun and regular summer water.

Other southern hemisphere treasures are the hoherias. The evergreen Hoheria sexstylosa is one of the best; its cultivar H. sextylosa ‘Snow Flurry’ is the most often available. Narrow and upright, growing quickly 15 feet or taller, it has half-inch-wide, dark green leaves and tiny flowers in abundant trusses that make a great display from mid-June to mid-July, depending on the heat at their peak bloom time.

Another good performer for me is one of a very large group of evergreen dogwoods from China, Cornus capitata. Though one of the more tender we grow, the cultivar C. capitata ‘Mountain Moon’, first brought to us by Piroche Nursery some years ago, gets leaf damage only when temperatures drop into the low teens. It should succeed in a protected spot in all but the coldest lowland areas. To 20 feet or more, this fairly narrow form has white flowers beginning in early May and lasting through June that only slowly age to cream and then chartreuse before producing pink, strawberry-sized fruit in fall and winter…fruit that—yes—does fall, and—yes—can make a bit of a mess just like lots of creatures we love. And by the way, the flowers (actually bracts) are large for any dogwood, measuring five to six inches across! Well worth careful siting away from foot traffic.

In areas with the warmest summers—such as the Willamette Valley— the crape myrtles (Lagerstroemia) should be mainstays. Coming in multiple sizes and colors, local nurseries grow dozens of cultivars. Crape myrtles are, again, for warm areas away from the ocean.

A couple of my favorites include: L. ‘Zuni’, to 15 feet with beautiful, flaking cream to light orange bark and deep rose purple flowers that in my garden begin anywhere from the end of June to mid July and last through the fall. Fall leaf color is said to be very good though we have not been so blessed. L. ’Natchez’, is a tall vase-shaped tree and one of the most appealing for its peeling, deep orange bark reminiscent of a madrone. It offers crisp white flowers from midsummer on. Full sun is best for earliest summer flowering and to guard against powdery mildew. All crape myrtles prefer deep, occasional summer watering—the further south the more necessary. Without water they cease growing in early summer and refuse to flower at all.

The following are two lovely deciduous trees. Fraxinus ornus, the ornamental ash, is a tough, Mediterranean species. While not a fan of ash trees in general —aren’t they planted on streets just to fall on your car after three years? —F. ornus is tough, sure-footed, and drought resistant. It has handsome dark leaves and, from the end of May through early summer, white trusses of flowers that become decorative seed clusters. Definitely one of the only ashes that should be tolerated on the local streets.

The second genus is Chionanthus. A couple of species available from nurseries are C. virginicus and C. retusus. The latter, from southeastern China, grows to 15–18 feet in a reasonable time, with particularly pretty, dark green sun-resistant leaves and flaking golden brown bark, somewhat resembling the paperbark maple (Acer griseum). White flowers adorn it from latest spring through midsummer. C. retusus remains fresh-looking even in high heat; I have seen plants performing very well even in inland southern California. We have ours planted with a background of star jasmine (Trachelospermum) where the dark green leaves set off the golden trunk and the jasmine’s white, early summer flowers echo the display above. Oh, and they smell really good, too.

And a few shrubs…

First the Carpenteria, one of the most important. Native to only a limited spot in the foothills east of Fresno, this dark, evergreen shrub can be kept as low as four to five feet by pinching, or—my preference—lifted into a large, vase-shaped shrub to eight feet or so, which shows off the structure and peeling golden bark. Three-inch white flowers resembling large anemones cover the shrub from the end of May through June or later. A number of cultivars exist, but basically they are all good. Planted with such native cohorts as Romneya coulteri…ok, at least 10 feet away!… these make a wonderful, drought-tolerant summer display. Another companion might be the lovely, variegated Iris foetidus with its white-striped leaves to complement the flowers above and contrast well with the dark foliage.

Many are surprised at the existence of a western native styrax, Styrax officinalis var. redivivus. Closely related to one in the southern Mediterranean, this deciduous, small, vase-shaped plant, to five or ten feet (if carefully coerced) has two-inch oval leaves and a basal burl capable of resprouting in case of… well, a brush fire or the more likely garden hazard, a tragic lawnmower accident. The flowers, often exceeding an inch long, appear from late spring through early summer followed by large seed pods that also add interest. In the hottest south and without water, the fall color commences in July following the buckeyes (Aesculus) into summer dormancy. Further north or with a little summer water the leaves are retained to turn a most pleasing golden in the fall. This creature, with another summer flowering shrub, the western spice bush, Calycanthus occidentalis, is found near seasonal seeps or creeks from southern Oregon through western California. With water C. occidentalis flowers through summer with burgundy, multi-petaled flowers settled amongst pleasing mid-green leaves. The fragrance is of a good red wine, though I must admit, on particularly hot days there are hints reminiscent of… Elmer’s Glue. You be the judge.

Another group of plants with which we've had great luck is the genus Bupleurum, particularly B. fruticosum. This evergreen shrub has glossy, almost succulent leaves, shiny and very long, looking almost Euphorbia-esque. Throughout the summer, plants produce umbels of chartreuse flowers that look like someone stuck fennel flowers all over. Ours is planted under the Mt. Etna broom, Genista aetnensis, for great, summer drought-tolerant contrast.

These few suggestions—favorites, of course—only hint at what you might find flowering on blistering summer days. More than you might think!

Sean Hogan collects drought-tolerant plants for his nursery, Cistus Design Nursery, in Sauvie Island, Oregon, www.cistus.com

lagerstroemia.jpg

A Lagerstroemia cultivar

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