Tree of Life Plants of the Year 2021

By Michael Erickson

August 19, 2021

Choosing plants that will not only thrive in their given microclimate but also create an interesting and dynamic garden is imperative in perennial design. Our design team is constantly looking for new plants and cultivars to utilize in our plantings and we wanted to share our five favorites from 2021.

#5 Geum triflorum – Prairie Smoke

Tolerating almost the full spectrum from full sun to mostly shade, Geum triflorum (Prairie Smoke or sometimes called Old Man’s Whiskers) has an insignificant nodding bloom. As one of the first prairie plants to bloom, Geum features fuchsia sepals disguised as petals while the petals are so tightly closed that bees must force their way inside to pollinate. Once the flower has been pollinated, the stems straighten to display wispy seedheads that imitate smoke. A beautiful garden addition, this plant is beautiful both in and out of bloom.

Geum flowers bow gently to the ground while pollinated flowers stand tall

#4 Anemone tomentosa ‘Robustissima’ – Japanese Windflower

Blooming at the opposite end of the growing season, this Japanese windflower is one of the very last flowers to bloom, lasting as late as October. Requiring a bit more moisture than many of our more xeric native plants, we tend to use anemone in low spots of gardens that collect more water. In the early and midsummer, A. tomentosa ‘Robustissima’ produces large grape-like leaves that provide foliar interest. Its late-flowering blooms are almost waxy in appearance and long stems raise the flowers above the dense mat of green leaves.

Anemone tomentosa ‘Robustissima’ beginning its bloom in mid September

#3 Astilbe x arendsii ‘rheinland’ – False Spirea

The Rheinland Astilbe grows in similar moisture conditions to the windflower, but will tolerate part to full shade, even building shade. Tall pink panicles of very small flowers bloom in late spring to early summer and gradually fade to a soft brown, providing textural interest throughout the summer and into the winter.

#2 Sporobolus airoides – Alkali Sacaton

While typically difficult to find at commercial nurseries, Sporobolus airoides is used in nearly every highway seeding project in Colorado. Highly tolerant of extreme stress and poor soil quality, Sporobolus airoides thrives in dry sun. Large airy panicle seedheads (similar to its cousin S. wrightii though not quite as large) can produce a billowy effect when planted in masses and once established. Sporobolus airoides is one of the first warm season grasses to produce seedheads, in mid to late June that fade from a slightly pink hue to blonde. While seedheads tend to deteriorate after snow, the soft texture of this grass will last through the summer and into autumn.

#1 Calamintha nepeta ssp. Nepeta – Calamint

The 2021 Tree of Life plant of the year and PPA plant of the year is Calamintha nepeta. This long blooming perennial thrives in dry sun, producing thousands of small white flowers, making the whole plant appear white. It remains very compact yet mingles well with other perennials such as Allium ‘Millenium’. With flowers in bloom from early summer until autumn, this perennial is highly attractive to dozens of pollinators. While calamint may spread under ideal conditions, we have found that in Colorado's intense climate, it tends to remain in its place in the garden. We are thrilled with how this plant has performed in several of our plantings from this year.