Recently, I went on a day excursion to the Denver Botanic Garden to identify some top garden performers for summer heat. Late summer has a tendency to wipe out a good majority of perennials. My interest was in those perennials that still had energy to bloom and put on a show in 90+ temperatures and occasional water. I should note that the plants I picked were thriving in the botanic garden AND in the average homeowner's yard, which would receive less care and attention than a plant in a public display garden.
Here are my top picks for late summer Front Range perennials:
Agastache rupestris Sunset Hyssop
This plant is just starting to put on a show in late summer. Normal bloom time is late July to frost. But, that is the appeal of the plant! When little else looks good, this plant takes center stage. It has delicate needle-like leaves and tubular flowers that attract butterflies and hummingbirds. The whole plant smells like licorice and is an excellent water-smart or xeriscape choice. It grows quite large (3-4' tall), but has an overall fine-textured look that allows it to blend very well with most any other plant combination. This plant thrives in full intense sun (native to the Southwest).
Salvia officinalis Variegated Sage
Sage is one of those garden plants that has so much to offer: aromatic foliage, great textured (rugose) leaves, kitchen and medicinal uses, interesting color variations, good form, low water needs, and great heat tolerance. It is categorized as a subshrub, has woody stems, and can have a presence even in the winter garden. I consider it an excellent border plant along walks and the front edge of a bed because of its perfect little hedgehog mounding growth habit. Even if it isn't used as a culinary tool, it is perfect for a children's garden because it is small, scented, and textured. And, it still looks amazing in August!
Echinacea purpurea Coneflower
So, this is a very common garden plant, but for good reason! Coneflower is blooming non-stop (with a little deadheading to encourage regrowth) from JUNE to frost--that is a serious garden statement. The plant doesn't flop or fade in the sun. It doesn't need supplementary water once established. Coneflower has few, if any pest or disease problems. It meshes well with a plethora of other plants without being overbearing to any given garden combination. Honeybees and butterflies love the plant. It is long-lasting as a cut flower. If left alone through the winter the old seed heads (where a flower used to be) create an additional season of interest. All it asks is full sun.
Caryopteris x clandonensis Blue Mist, Bluebeard, Blue Spirea
Blue Mist shrub is easy to grow, adaptable to various soils, and somewhat drought tolerant.
It begins flowering in late summer (usually mid- to late July) and continues until frost. Blue flowers are always a welcome and somewhat rare garden feature, so this plant has great design versatility and works well in a shrub border or mixed border with other types of perennials. I prefer this plant to other upright purple/blue growing shrub-like perennials (such as Russian Sage) because it has a much tidier growth habit and will not self-sow itself with abandon. The leaves are aromatic when rubbed, the flowers have a sweet fragrance, and it attracts bees and butterflies. Overall plant size is usually 2-3' tall and wide, prefers full sun or light shade.
Today is my official due date; I made it to 40 weeks! Apparently less than 5% of women deliver on their due date, and it appears that I am not in that five percent. Nothing much is happening yet, just wanted to report I am still out here, waiting.
