A PASSION FOR PLANTS: July 2007
by Nancy Schramm
When the mercury starts climbing each summer, I gravitate towards the shady parts of the garden. My very favorite spot is under some mature valley oaks (Quercus lobata). As soon as I cool down a bit, I start looking around and thinking about planting the area. But planting under mature native oaks of any kind must be done with extreme care, since summer irrigation can eventually be fatal to these magnificent trees. What you need are plants that will thrive in dry shade. This is a useful group of plants to know about. Some of the best choices for this situation are our very own California natives. Let's look at a few plants that are especially appropriate, mostly natives, but some pleasing introductions, too.
Yerba buena (Satureja douglasii) is a minty-scented ground cover with small, roundish ruffly leaves. It's evergreen, and when pinched regularly it can form a nice dense mat. The dried leaves make a lovely tea.
Coral bells (Heuchera) is a genus widely hybridized in recent years. The crosses that have H.maxima in their parentage are some of the most drought tolerant. Coral bell leaves are lobed and scalloped and come in many colors including green, purple and peach. These clumping plants can be used as a taller groundcover with the foliage ranging 1'- 2' tall, and the flowers up to 2' or 3' tall. The flowers are indeed tiny bells on long stalks that stand in white, pink, or red masses above the foliage.
If you're looking for a bold textured ground cover, take a look at Bergenia. The large round leaves have a lush appearance, belying how tough these plants really are. They get about 1?' tall, and spread wider. The clusters of open bell-shaped flowers are held nestled in and slightly above the foliage, and are found in many shades from white and pink to purple.
For some pure joy, grow the native Iris. There are several species available and many gorgeous hybrids. Plant height can range from less than 1' to over 2?' with leaves that are long and narrow. Have some fun and go shopping when they're in bloom during the spring and early summer. You'll find a rainbow of colors. I've also had good luck naturalizing Iris unguicularis, the winter iris, which can bloom all winter long.
There are two native ferns that add a soft touch to our shady landscape. The western sword fern (Polystichum munitum) can reach 5' tall, although 3'- 4' is more typical. The fronds start out erect, then arch outward from the crown. The fronds of the coastal wood fern (Dryopteris arguta) are shorter (1'- 2' long) but wider (4"- 6"). Both ferns look lush and green year 'round, and are relatively easy to grow.
The hellebore (Helleborus) is another genus that has received plenty of attention from hybridizers. Several of the species will take dryer conditions; look for H.argutifolius, H.foetidus, and H.lividus. All hellebores start blooming in the winter and continue into spring. The clustered, bell-shaped flowers will persist on the plants for quite awhile, providing long-term interest. The leaves are very attractive, often toothed along the edges. Their shape is called palmate, which means they are divided into leaflets that connect in the middle (like a hand).
Heavenly bamboo (Nandina domestica) can fill the need for a taller plant. (2'-8' tall, depending on variety) It has a delicate, lacy appearance (like true bamboo), so even the larger varieties don't look overpowering. The new leaves open pink and bronzy, and most turn very red during the winter. The whitish flowers are held in erect, open clusters. Red berries develop best when there are two or more plants.
Finally, for what can be quite large shrubs (possibly up to 6'-12' tall) the pink flowering currant (Ribes sanguineum var. glutinosum) and fuchsia flowered gooseberry (R.speciosum) are both lovely native choices. The leaves are small and lobed, like a small rounded maple leaf, and give the plant a fine texture. The flowers, although small, are produced in such quantity as to be spectacular. The flowers are attractive to hummingbirds, and since they bloom early in the year can provide a valuable source of nectar. Just beware, the gooseberry has enough wicked spines to give any unwary passer-by an unpleasant greeting.
Yes, there are more choices, such as Cyclamen, a bulb with a flower that looks 'in-side-out' and a native bunchgrass called Festuca californica, but I'm out of room! Note: The Iris, Dryopteris, Helleborus, Nandina, and Ribes are deer and rodent resistant.
Resources: Native Treasures: Gardening with the Plants of California by M. Nevin Smith, California Native Plants for the Garden by Carol Bornstein, David Fross, and Bart O'Brien.
Local sources: Elkhorn Native Plant Nursery, Native Revival Nursery, Terra Sole Nurseries
Catalog sources: Digging Dog Nursery, Forestfarm.
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