Planting Microclimates
by Eric Larusson
The right plant in the right place" is the first rule of landscape design. It was the first rule I learned, yet in spite of such wisdom, I've pushed the concept this way and that. I've even broken the rule more than a few times, always with regret. Nature is a harsh critic. If a plant is in the wrong place, it either adapts or dies.
As with many aspects of landscaping in this region of garden challenges, I look to nature for design inspiration. In the nursery, you will frequently hear us asking questions about which street you live on, in which subdivision, and where, in relation to your home, you'll be planting. We are attempting to ascertain the details of the microclimate you'll be planting in. Microclimates are created by buildings, trees, fences, roads, hills or lakes. A microclimate may be very different from the overall climate of the region, and your garden might have several different ones. Most of us also contend with poor soils: various forms of rock, from boulders to dust. These two factors taken together–microclimate and soil–dictate the type of plants—or, as they are referred to in the wild, the plant community—that will grow there; and in whatever microclimates you're planting in, there is a matching natural location in the Sierra with a "native garden" that has thrived.
Southern Exposure
Sunny south-facing slopes suffer the harshest of extremes. When the snow finally melts off in spring, the plants are exposed to intense, high-elevation sun and dry winds. At night, without the insulating blanket of snow, plants Most successful Tahoe gardens group together many different gardens, each with plants perfect for their own microclimate.
Deep Freeze
In shade, plants at high elevations may pop out of the snow as late as mid-summer, having only August and September to store up the reserves needed to survive the next ten months of winter; correspondingly, they must be able to conserve and ration this stored energy for these long periods of time. Thus, in addition to needing to be efficient photosynthesizers, plants that survive in these conditions must be very flexible or very strong, and their roots must anchor securely. Because the long, slow snowmelt near streams (riparian areas) and in the meadows creates a growing climate similar to that found in north-facing shady slopes, these areas share similar plant communities. Many of these plants likely associate with mycorrhizal fungi that may, in turn, share nutrients with the trees; thus the smaller plants actually receive nutrients from the trees, second-hand.
Residents on Tahoe's West Shore and the south side of Donner Lake—places where the sun doesn't clear the hilltops until June—know how long the winter can seem, even in lower elevations. Snow sheds from metal roofs to the north side of some homes create frozen glaciers that can last for months.
If you look to the lush cool shade at the base of a north-facing cliff, you will likely find a thriving plant community: mountain pink Spiraea, Sierra currant, thimbleberry, twinberry, Mitella, lilies, ferns, columbine, meadowrue, mountain bluebells, mountain forget-me-nots, snowberry, baneberry, Sierra primrose, violet and angelica, Pyrola, Salomon's seal, groundsel and asters
Red fir, mountain hemlock and silver pine are found up high while white fir, lodgepole and cedar are found at lower elevations. Aspen, Scouler's willow, mountain ash, mountain maple and serviceberry are also often found in the moist north and east slopes.
Many of the native plants found in this community are available in nurseries. Here's a few common substitutions we use: European mountain ash, coral bells, ostrich fern, leopard's bane, bugbane and garden varieties of forget-me-not, Primrose, columbine, bluebell and violet.
Boggy
For most plants, air (oxygen) in the soil is as important to plants' roots as water. In saturated soils, there is very little to no air. Plants adapted to wet meadows, marshes and swamps have the ability to move air to the roots to keep them alive and growing. Some of the plants near the margins of wet areas have some of their roots in water and some of their roots in higher ground.
As a gardening difficulty, few homes have a natural bog to contend with when trying to find plants that will survive in the landscape. Many gardeners now, however, are building ponds and intentionally creating bogs to complement them.
Most of the plants listed above that can survive the deep freeze will also grow well in moist shade. Additional plants that occur in our natural wetlands include: meadow Penstemon, cow parsnip, ranger's buttons, blue-eyed grass, swamp onion, shooting star, blue flag Iris, lupine, mallow, monkeyflowers, veronica, Cammasia, goldenrod, cinquefoil, mountain strawberry, buttercups, Delphinium, monkshood, bistort, horsemint, Jacob's ladder, wild rose (interestingly it is extremely drought tolerant as well), mountain alder, willow species (we have at least eight native species), red elderberry, black cottonwood and—the conifer that tolerates the wettest soil—lodgepole pine.
There are many more habitats and microclimates that support a variety of plant communities in the northern Sierra. If you consider the plants of the Cascades, the Rockies or any other similar mountain ranges, there are many sources of inspiration. If you garden, hike often and look for inspiration in the gardens nature has provided us in this spectacular place we live.