It’s solstice time, the longest day of the year. With the sun at its highest, we enter the so-called dog days of summer when the dog star or Sirius rises at the same time (or nearly so) as the sun in the Northern Hemisphere.
In year’s past, especially in droughty summers, a favorite fieldtrip was a visit to arboretums or public gardens where watering was a luxury they could not afford. The observation of stressed plants, the ones that don’t whimper or pout about the situation nor die from the hardship might be those you want to have in your own garden. For me there were certainly favorites which I chose because they are; able to take it hot and dry, be long lived, do not spread in an overly aggressive manner, offer a relatively long season of interest.
Perennials are my wheelhouse and I would like to list a few favorites, plants that stand up to the heat while many of us would prefer to be inside. First and number one is Calamintha ‘Montrose White’. Even when temperatures hit 100 degrees, there is no sign of wilt. In the mint family, a clump grower with woody stems that grow to twenty inches, tiny white flowers cover the stem for two months. Rich in nectar, bees adore them. Tiny leaves are que to its superpower, the smaller or narrower the leaf, the more drought tolerant they are. Sun is best for calamintha, from sunup to sundown if possible. Coreopsis verticillata with its narrow foliage is another perennial that can take a lot of abuse. A sun lover as well, south or southwest for planting sites. Small yellow daisies persist for six to eight weeks and this perennial is native to Virginia and Maryland. Amsonia hubrichtii or Hubricht’s blue star is an amazing perennial for areas too harsh for others. Narrow foliage on stems to four feet and more, the summer movement is like an ornamental grass. Fall color is often the reason to grow amsonia (there are pale blue flowers in spring) and this one does not disappoint. Native to south-central parts of North America, when planting allow four square feet per plant.
Artemisia, perovskia or Russian sage and nepeta (catmint), all are satisfactory albeit non-native. The grayish foliage comes from hairy leaves which aid in retention of moisture during dry periods. Others that are white or gray and suitable for drought are lamb’s ears, dusty miller, and lavender. One can also find suitable heat lovers from our warm season, native grasses. Little bluestem is a good choice, particularly when one finds gray leafed selections and an upright habit such as Schizachyrium ‘Standing Ovation’. Reaching three feet, there is a gentle sway with summer breezes. We are not “sage land” with deserts in our backyards but we can certainly borrow from that landscape. Plants like thyme, sedum, sage or salvia and various succulents are options for sunny places.
In the shade garden, the fight for water is elevated. Tree roots, particularly those with fine fibrous surface roots can be nearly impossible to garden under. Maple, beech, and cherry are examples of overly challenging understories. Epimedium or barrenwort seems to be singularly capable of the battle. A groundcover (in time), the spread comes from underground rhizomes. This perennial can live through abuse that few others will tolerate. Nice flowers, foliage turns coppery in fall, and the leaves are semi-evergreen. Not a native, but certainly not a problematic plant. Iris tectorum, a Chinese iris, and Solomon’s Seal or polygonatum are others that score high. In native perennials I love Christmas fern and hayscented fern. The latter is a spreader, light green and dainty looking, a case where looks can be deceiving.
Given the choice on hot summer days, there are options beyond the bedraggled, wilt prone plants. Some actually do like it hot.