At this time of year, most blooming plants have finished their show and are just enduring the heat until the rains come. Buddleia, phygelius, fuchsia, echinacea, and cistus still offer a few blooms, thank goodness, but late summer / early fall is not when they shine. Here are 7 of my favorite plants that bloom in late August or early September in my garden.
Albizia julibrissin, or Silk Tree (above photo), is an elegant, feathery tree that has a broad canopy and delicate, divided leaves. In August, fan-like, wispy flowers of white and pink cover the surface of the foliage, providing a stunning, tropical look. I love how the flowers sit atop the leaves instead of hang beneath. There’s a purple leaved cultivar named ‘Summer Chocolate.’ Though it likes to bake in the sun, it does have a few drawbacks: the branches can break during strong winds, leaving wounds in the main trunk, and it’s susceptible to verticillium wilt. It also leafs out much later than other trees. But given it’s own sunny space, the tree is a graceful, eye-catching specimen.
Caryopteris x clandonensis, or Bluebeard, is a tough shrub, hardy down to Zone 6. It matches well with our Mediterranean-like summers in the Northwest. It’s drought-tolerant but doesn’t mind our winter rain, needs little to no pruning, and in August blooms with pretty blue flowers. Sometimes branches can be brittle and twiggy but cleaning them out is easy enough. Caryopteris ‘Sunshine Blue’ is a yellow-leaved cultivar that literally does glow like a sun. It will pop with color from far away. It has lighter blue flowers but the foliage really makes this plant worth growing.
I have Clerodendrum trichotomum, or Harlequin Glorybower, planted not far from my patio so I can smell it when it blooms. The fragrance is strong and spicy! It’s known for spadal leaves that smell like burnt peanut butter when rubbed, but that smell is nothing compared to the white starry flowers in bloom. After the flowers fade, shiny, blue berries take their place for a beautiful pattern of pink and indigo. Drawbacks to this small tree include its running habit, where small stalks emerge near the mother tree and its weak, crunchy, breakable stems. Still, the scent of this tree in the heat of August can not be beat! Just don’t prune it, otherwise it will grow into an ugly mess.
Lagerstroemia indica x fauriei ‘Zuni,’ or Zuni Crape Myrtle, is one of my favorite trees for a Seattle yard. You can spot it from a mile away. Stunning magenta flowers, pretty mottled bark, and tight glossy foliage. It’s a smaller, multi-stemmed tree that fits nicely in the corner of a city yard. It needs little care save for a hot sunny location and good drainage.
Rudbeckia hirta, Black-eyed Susans, are an oldie but a goodie perennial. I love the bright, cheery daisy-shaped flowers and sunny color. When happy, Black-eyed Susans, spread voraciously so watch out. But it’s easy enough to put a spade in the ground, cut some out, and pass them onto neighbors. My only complaint generally with Black-eyed Susans is in winter they leave stringy threads about. There’s a cool cultivar called ‘Cherry Brandy’ that has cherry-colored petals with a blackish center. This is more of a bushier, self-contained perennial, rather than thin-stemmed and spreading. It has bold color. If you’re a newbie gardener and want to grow something low-maintenance, any Rudbeckia is a great choice.
Sedum spectabile ‘Brilliant’ is a succulent perennial that grows in poor soil with little water. It starts out with cute rosettes in early spring that then elongate into rubbery stalks whose flat flowers turn from bright pink, to red, to maroon, and finally brown. Even though the stalks dry during autumn, they hold their shape, offering nice structure for winter. And birds feed off the seedheads. Sedum ‘Brilliant’ is an easy care perennial that I do little to except for cutting away dried stalks in early spring. If you plant Sedum ‘Brilliant’ or ‘Autumn Joy’ and the stalks flop over, it probably means your soil is too rich. Think desert conditions with these plants. Sun, well-draining soil, rocks, etc.
Vitex agnus-castus, or Chaste Tree, sends out spikes of a long, blue inflorescences during the hottest part of the season. This tree likes to bake in the sun, and though I call it a “tree,” it’s really more of a tall shrub, forming a rounded habit that will bounce back surprisingly even after the toughest winters. It also loves dry conditions. Good for a parking strip.
For more information on these plants, check out the Oregon State University landscape database. Happy gardening!