Growing wild penstemon species
When I moved to Grass Valley in 1992, I bought a house, which was surrounded by two acres of old overgrown manzanita. A fire trap to be sure. After hiring a brush-clearing firm, Hillside Landscaping I was left with an acre of bare red dirt and a few scattered oaks trees.
I immediately set to work transforming this barren landscape into a garden. I put up a deer fence and built a path system-all the while thinking about what I would plant in my new garden. Because I have a low output well, I was restricted to drought tolerant plants. And because I wanted to create an eco-friendly garden, I chose to plant California native plants.
I decided to experiment with as many different species of penstemon as possible. I had observed several spectacular species in the wild and hoped they would grow well in the garden. My research told me that wild penstemons are tricky to grow and can be short-lived in the garden. Their primary requirement is well draining soil and many of them require minimal irrigation. For those gardeners with poorly drained clay soil, one solution is to import a good sandy loam from a soil vendor and mound it up on top of the existing soil. Both Eaton’s penstemon (P. eatonii) and P. pseudospectabils have thrived in my garden on mounded sandy loam soil. They receive morning sun and are shaded by tall pines in the afternoon. Both these plants form sprawling clumps and have semi-upright stems with tubular flowers that attract hummingbirds. Eaton’s penstemon has red flowers and P. pseudospectabils has outrageous red/pink/pruple flowers that defy description. Both are native to mountainous areas of the southwestern states, but can flourish here in the foothills.
The trick when watering penstemons is to give them enough to keep them looking fresh through the summer, but not too much, otherwise you can kill them with kindness. Many of the penstemon species that inhabit dry desert and mountain habitat in the Southwest, can survive the summer without irrigation once they are established in the garden. But after a long dry summer without water they will look pretty ratty. A more practical solution is create a semi-dry border by combining penstemon species with wild buckwheats, monkey flowers, California poppies, salvias and other drought-tolerant native plants and drip irrigating once every ten days in the summer, beginning in May. This will keep your plants looking fresh and extend their bloom well into the summer. In the Sierra foothills of Nevada and Placer Counties, azure penstemon (P. azureus) and foothill penstemon (P. heterophyllus) are native wildflowers. A hybrid of these two species called Penstemon ‘Margarita BOP’ is one of the easiest penstemons for garden culture. This hybrid was discovered next to the back porch at Las Pilitas nursery in Santa Margarita, Calif-thus its name Penstemon ‘Margarita BOP.’ It forms an evergreen, 3-ft wide sprawling mound covered with masses of tubular blue and purple flowers. Dave Roberts, President of EcoLandscape California, a non-profit ecological landscaping organization, grows P. ‘Margarita BOP’ in his Sacramento garden. He grows it in sandy soil and waters it once a week during the summer, beginning in May, which keeps the plant blooming and looking fresh through the summer.
Several penstemon species have persisted and thrived in my garden without any special improvement of soil drainage. They are all planted in full sun on a west-facing slope. Beginning in May, they are drip irrigated once every two weeks through their first summer after being planted in the garden. During subsequent years, I water them sparingly through July and then cease watering for the rest of the summer.
My hand’s down favorite has been Penstemon incertus. I grew it from seed that I purchased from the Theodore Payne Foundation in southern California.
The plant is clump-forming with multiple 2-foot tall stems, grey green foliage and beautiful blue/purple tubular flowers. It is easy to propagate from cuttings and seed and is now abundant in my garden. My original plant is still thriving after four years. Royal penstemon (P. spectabilis) has also thrived in my garden without soil improvement. This is a gorgeous three-foot tall clump-forming plant. When in full bloom it is covered with blue, pink and purple flowers and buzzing with visiting honey bees. Grinnell’s beard tongue (P. grennellii) also grows on a hot,Hillside Landscaping rocky slope in my garden. It reaches about two feet in height and has multiple stems with coarsely-toothed shiny green leaves. It has puffy balloon-shaped flowers that are lightly scented and colored pink with delicate mauve tracings. This species is very sensitive to over-watering and should not be irrigated in summer. I recommend planting this plant in a sandy loam of decomposed granite soil if possible.
I have also experimented with several species of keckiella, which are the shrubby cousins of the perennial penstemons. They are sometimes called bush penstemons. My resident hummingbird loves the scarlet-colored tubular flowers heartleaf keckiella (K. cordifolia) in my garden. Bees favor the snapdragon-like flowers of yellow keckiella (K. antirrhinoides) in my garden.
All the penstemon species are very easy to propagate from cuttings or seed. I usually leave the spent blooms on some of the stems so that seed pods can develop. I harvest the seed and sow it in pots in the fall so that it is watered by winter rains. The seedlings germinate en masse in early spring. I transplant these directly into the garden or into 4 inch pots-in which case, I grow them through the summer and then plant them into the garden in fall.
Cuttings are easier. I usually wait until February and then cut year-old stems back to sprouting buds near the base of the stems. Then I cut the pruned off stems into 6-inch long sections, and stick these directly into the ground around the parent plants. With a little extra water, these cuttings root quickly and easily. In this way, as older plants die off, new young ones grow up to replace them.
All of these penstemon and bush penstemon species (plus many other California native trees, shrubs, perennials and grasses) will be available for purchase at the Spring Native Plant Sale and Wildflower Show at the Rocklin campus of Sierra College (Parking Lot S) on Saturday, May 3rd from 9:30 am to 1:30 pm.
Quantities of some of these are limited, so come early for the best selection. There will be a special presentation “Wildflowers of Placer and Nevada Counties - Where to See ‘em and How to Grow ‘em” before the sale at 9 am.
Tags: amp, blooms, drought, fence, grass, grasses, Hillside Landscaping, irrigation, landscape, Landscaping, Landscaping Rock, native plants, perennials, plants, poppies, porch, salvia, sandy soil, seedlings, shrub, shrubs, soil, soil and water0
Sunday, April 27th, 2008
