The Overlooked Understory
By Panayoti Kelaidis:
Everyone loves trees; we still have people complaining about the removal of a hollow weeping willow from Denver Botanic Gardens—DECADES ago! Then of course there’s lawn worship (just cruise any upscale neighborhood). If you need to be convinced people love flowers, visit any mountain town in Colorado where they know that the more petunias and hanging baskets, the more tourists.
But what about shrubs? Or as most people refer to them, the “bushes”. More often than not these are stuffed up against walls or foundations or isolated in a corner of the garden, like a wallflower at a dance.
Savvy gardeners quickly learn that shrubs provide a vast array of services. Nothing hides an ugly view faster or better than a shrub. They make great walls (even if you like your neighbor). They can provide a dazzling focal point in bloom, or in fall color. Best of all, most shrubs require very little attention or care and can live for decades (or even centuries in some cases). Show me a posy that can do that!
There are potentially thousands of attractive shrubs that could be grown in Colorado. I can’t even begin to count how many we’ve grown at Denver Botanic Gardens (and barely scratched the surface) but there are a few that have proven their mettle and are still rarely seen in Denver area gardens. Here are my ten favorites. Time to start planting them again!
1 Kolkwitzia amabilis is aptly called “Beauty Bush” as a common name. I have seen it perhaps a dozen times in our area, almost always in gardens 100 or more years old —where they’ve persisted and now form spectacular specimens 10 or more feet high. The outstanding feature of this plant is its graceful arching habit.
The soft pink flowers come at the height of spring and last for several weeks making a wonderful spectacle. I am a bark man; I love the incredible shredding and dramatic bark on aging specimens of these that must be seen to be believed.
2 Syringa vulgaris (Persian Lilac). Who doesn’t know lilacs? The heavenly scent? The gorgeous lavender, nearly blue, white or even pink flame-shaped panicles of bloom that elbowed into the first lines of two of the greatest poems in English by Walt Whitman and T.S. Eliot. Lilacs are steppe plants from Central Asia, tough as nails and xeric to boot. Why aren’t they seen in any but the oldest neighborhoods? Because you haven’t planted any recently, that’s why!
3 Blue holly leaved Mahonia, Mahonia haematocarpa. Good old Oregon Grape (Mahonia aquifolium) is usually stuffed in dense shade where it grows, but the best one I’ve ever seen grew spontaneously in Dryland Mesa at Denver Botanic Gardens in full sun, never watered. Even tougher, it’s southwestern cousin smothers with yellow flowers in May and bright red fruit in late summer. Often grown by specialty nurseries in the Southwest, this one has it all.
4 Seven Sons Flower. Heptacodium miconioides I too have no clue who these seven sons are. I do know that even though Plant Select has promoted this, you rarely see it in gardens. Gorgeous bark, attractive foliage, and stunning white flowers in late summer transform into bright scarlet fruit. A tough adaptable plant that’s much too rare in local gardens.
5 Spiraea spp. There are numerous species of Spiraea, almost all have gorgeous flowers, attractive habit, and fall color. I have seen these persist in abandoned gardens. They come in all sizes and forms and have a measure of drought tolerance.
6 Mock Orange Philadelphus spp. Any plant that smells like citrus flowers is a friend of mine. This large genus is found all over the world, but none can beat our native P. lewisii (state flower of Idaho) which forms an arching graceful mound that’s attractive throughout the season. P. microphyllus found over much of Colorado has beautiful silvery leaves and is very xeric once established.
7 Evergreen Mountain Mahogany. Cercocarpius ledifolius. Why anyone would plant deciduous (and rather messy) privets when you can have this graceful, extremely xeric and EVERGREEN native plant is beyond me. Surprisingly fast growing, it is also capable of thriving without any supplemental irrigation.
8 Winged Euonymous Euonymus alata This makes a compact, rounded shrub in Colorado that reliably turns a brilliant eye-blinding vermilion scarlet in the fall. I’ve read this is now not sold in much of the Eastern USA. I have never seen a self-sown seedling in Colorado: PROOF POSITIVE that “invasiveness” is a function of climate. Ignore the bad (uninformed) press and plant this gem.
9 Fernbush Chamaebatiaria millefolium Few shrubs thrive with no irrigation on the worst clay or sandy soils. This makes a compact mound of lovely silvery fern-like leaves that erupt into countless corymbs of ivory white in July when it is mobbed by bees, butterflies and nearly every other invertebrate under the sun. I love the spicy, balsam-like fragrance of the foliage. I don’t think I’ve stumbled on this plant anywhere outside a few sophisticated local gardens. That’s plain WRONG!
10 Siberian pea shrubs Caragana sp. A treeform Caragana grew in the park next to where I grew up in Boulder. It’s still there—I won’t say how many decades, but a lot! There are dozens of species in all shapes and sizes. All are Zone 3 or colder-hardy. Many are Zeric. When the yellow flowers are in bloom they resemble a giant broom.
Many of these were popular way back in the last Millennium. There’s a reason for that...and it’s time to bring them back!
Panayoti Kelaidis is senior curator & Director of Outreach at Denver Botanic Gardens.
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