Prepared by SWNEC Ecologist, Stefan Weber
Whether summer arrives early or leaves late, selecting drought tolerant plants for our gardens is increasingly important. Approaching garden design with an aim to reduce and eliminate the need for irrigation is called xeriscaping. Ontario’s native species are some of the best choices. Not only are they well adapted to our hot summers and cold winters, they are the best at supporting native wildlife as well, especially goldenrods and asters.
When designing your garden, make sure not to over-mulch the soil. This can actually prevent moisture from reaching the roots. A thin layer of fine shredded or straw mulch is best, no more than 3-4cm. A living mulch, or green mulch of low growing perennial plants is even better at shading the soil and keeping moisture in the ground.
Tallgrass Prairie species like Culvers Root and Ironweed have deep roots and can definitely take the heat, but also grow very large, and can by too messy, floppy or unruly for a small garden, an urban garden, or a public space. The best plants are some of our most uncommon and unusual and are found in savannahs, alvars, and sand barren habitats.
Prairie Smoke (Geum triflorum): Deep pink flowers in spring give way to a smoky cloud of seed pods in summer. G. triflorum spreads slowly, but stays very short. This alvar species thrives in a rock garden and looks great in a mixed border.
Field Pussy Toes (Antennaria neglecta): full sun and poor soil is no match for this little ground-cover. Producing silver and yellow flower heads in spring, followed by a flush of new leaves turning silver and then evergreen.
Whorled Milkweed (Asclepias verticillata): Does your garden resemble Sahara in the summer? Do you want to attract butterflies? This is the milkweed for you! Whorled milkweed is the smallest and most drought tolerant of our milkweed species. It also also the longest boom period, and is easy to divide once mature. Creamy-peach flowers sprout almost all summer amongst dark grassy foliage.
Dwarf Blazing Star (Liatris cylindracea): A pollinator magnet, with fuchsia flowers in the mid to late summer. Unlike other blazing star species, Dwarf Blazing Star has low sprawling stems, punctuated with fuzzy flower heads.
Hairy Beardtongue (Penstemon hirsutus): Another alvar species, Hairy, or Pink Beardtongue blooms in late spring and early summer. Foxglove-like flowers are held above the low growing foliage on slender spikes. Bumble-bee approved!
Frosted & Slender Vervain (Verbena stricta, V. simplex): These species grow in thin soils in full to part sun. Slender Vervain is very short, and produces lilac coloured flowers in early summer. Frosted Vervain on the other has much brighter pink flowers, but can grow to almost one metre.
Honorable Mentions: Nodding Onion, , Upland White Aster, Wild Strawberry, Grey Goldenrod, Smooth Aster
Pale Leaved Sunflower (Helianthus strumosus): With lemon yellow blooms in late summer that attract butterflies, this sunflower only grows up toe 1m, but will spread widely in well-drained soil. Loves dry, shady sand.
Silver-rod, (Solidago bicolor): One of the prettiest native Goldentod species, the Silver-rod has a mix of creamy yellow and pure white florists that wrap around a longer, slender stem. It thrives in part shade on well drained soil
Large Leaved Aster & Heart Leaved Aster (Eurybia macrophyla, Symphiotrichum cordifolium): Though similar in appearance, these two different species of woodland aster bloom in early fall. Flowers range from white to bluish to pinkish. The Large Leaved Aster spreads like a groundcover, keeping its big leaves close to the ground, and forming an airy, float-topped inflorescence. The Heart Leaved Aster stays in a dense, bushy clump and flowers later in the season.
Honorable Mentions: Wild Columbine, Wild Ginger, Yellow Pimpernel, Hepatica