Using Grasses in the Garden
Laura Lovett
Native grasses mingle with checkerbloom and Douglas iris at the San Francisco Botanical Garden. Photo © Saxon Holt, Photobotanic
No native plant community in the wild exists without species of grasses as part of the habitat, but gardeners tend to be hesitant about including them in their home gardens. Mixed with perennials and shrubs, anchoring a hot dry site, or cascading down a slope, there is a grass species that will thrive in any sun or shade exposure.
Compared to annual grasses, perennial grasses stay green long into the summer on little or no water, making them less flammable than alien annuals. They are deep-rooted, stabilizing surface and sub-soils once established. They help to build soil organic matter, thereby increasing site fertility and sustained productivity. Perennial grasses mixed among flowering annuals and perennials or as a groundcover under shrubs are an excellent way to provide interest in the garden.
Grasses are generally categorized as cool season or warm season. These labels refer to the season when the grass will put on green growth. Cool season grasses are green in the spring and all through the fall when temperatures are around 65-75°F. They will require more water to stay green in a hot summer as it is their normal dormant period. However, they will thrive better if given a chance for some dormancy. Cool season grasses should be planted in the fall.
Warm season grasses will green up as summer temperatures go up but go dormant and turn brown in areas with a cold winter. These grasses should be planted in the spring. Warm season grasses flower and produce seed at the end of their summer growing season, while cool season species are productive in the spring and fall when temperatures are cooler and will flower late in each season.
Perennial grasses are slower than many annuals in establishing themselves. Regular weeding is necessary to keep competing annual grasses and weeds from shading out new seedlings until they get established. They need to be planted away from the immediate 2–5 foot perimeter of the house and maintained by mowing at an appropriate height. Both the height of mowing and the timing of it are key to encouraging the native perennial grasses and discouraging annual weedy grasses. See our article, Using Native Grasses in Landscaping, for full details on planting and mowing to achieve the look you want.
Many gardeners plant native grasses in drifts interspersed with common grassland flowering forbs such as Douglas iris, checkerbloom, monkeyflower, California fuchsia, goldenrod, yarrow, buckwheat, and blue-eyed grass. Deer don’t eat grasses, however, they may nibble on the perennials planted among them.
We will be offering these grass species at our Fall Plant Sale:
California Fescue, Festuca californica
A beautiful, medium-height, perennial bunchgrass with a host of uses almost anywhere in the garden. A good choice under native oaks with light shade, or in part shade. Accepts full sun near the coast. Easy and fast to grow. Drought tolerant once established but looks better with some summer water. Gets 2 x 2 feet, with seed heads to 4 feet.
Elk Blue Rush, Juncus patens ‘Elk Blue’
Elk Blue Rush features exceptionally blue foliage and a vigorous spreading habit, forming upright clumps of narrow, grey-blue stems. This selection is shorter than the typical grey rush, only reaching about 18 inches tall. It likes moist soils, making it a great solution for bioswales or rain gardens.
Deer Grass, Muhlenbergia rigens
Deer grass is a 3 foot evergreen perennial with 2 foot plumes rising above the plant. It is fast growing, normally reaching mature size in a season or two. Excellent as a specimen plant or to add size and drama to a perennial bed. Plant in full sun to light shade.
Stipa hymenoides – Indian ricegrass
Indian Rice Grass, Stipa hymenoides
A perfect plant for dryland gardens or drought-restricted areas. It typically grows up to 2 feet tall and a foot wide. The branching, wavy flower stalk and seed pods are so unique that it’s often used in flower arrangements. It can live in sand to clay but does particularly well in sandy soils and is an excellent choice for soil stabilization.
Lagunita Wild Rye, Leymus triticoides ‘Lagunita’
A perennial, cool season, evergreen clone of our native creeping wild rye. ‘Lagunita’ will stay at 10-16 inches. It is great for erosion control and can also be used effectively as a base groundcover grass for meadow installations and orchard understory. Sun or part shade.
Festuca idahoensis ‘Siskiyou Blue’
Siskiyou Blue Fescue, Festuca idahoensis ‘Siskiyou Blue’
This clump-forming hybrid of the native Idaho Fescue is notable for its beautiful spruce-blue foliage. The thin leaves are much longer than the more familiar Festuca glauca, giving ‘Siskiyou Blue’ a softer, more graceful look. Takes sun or light shade. Good with moderate to occasional irrigation.
Anthoxanthum occidentale – vanilla grass, CA sweet grass
Vanilla Grass, Hierochloe occidentalis (Anthoxanthum occidentale)
An excellent choice for woodland gardens as it is compatible with many redwood forest plants. Prefers soil high in organic matter. Best with some summer water but is drought tolerant near the coast. The leaves offer a sweet vanilla fragrance when dried. Gets 1–2 feet.
What could be more delightful than butterflies flitting around your garden? If you’d like to increase their numbers, there are some simple things you can do. Butterflies go through four life stages: the egg, larva (caterpillar), pupa (or chrysalis), and the adult stage—the butterfly. At each stage, specific needs must be met for the insect to progress toward the final adult form and begin the cycle anew. By selecting the right variety of native flowers that flourish in your microclimate, you can contribute significantly to supporting their populations.
