Plentiful options for dry summer gardens
Published: Thursday, June 20, 2013 at 3:00 a.m.
Last Modified: Wednesday, June 19, 2013 at 1:52 p.m.
Our halcyon spring weather has been especially kind to gardens this year. Growth erupted earlier than usual, plants breezed through our brief heat waves, blooms flourished beyond expectations, and black spot on roses still remains in check.
When gardens appear this impressive going into summer, it's tempting to broaden our plant palette and turn to species we might otherwise shun.
Broad-leaved hostas lure us. Should we consider more azaleas? What about adding a few fluffy filipendulas or astilbes? More daylilies (Hemerocallis) or some bright red cardinal flowers (Lobelia cardinalis)?
Savvy gardeners know that these and other moisture lovers suffer during our dry summers, not only from lack of constant soil moisture but from dry air as well. It takes heavy irrigation to maintain healthy roots and foliage of many alluring non-Mediterranean species, moisture that supplies nurturing conditions below ground as well some humidity above.
Where water is plentiful, there is no dilemma, but that scenario is rare anywhere in California. Most of us don't have the luxury of unlimited supplies for long and frequent irrigation.
With a little planning and careful selection, however, we can still enjoy most of the effects that moisture-lovers bring to our gardens by opting for drought-resistant, climate-appropriate species with features evocative of more thirsty cousins.
Right plant, right place
I remember talking with a fellow gardener some years ago about why her hostas were not doing well, not as lush and wonderful as she had hoped. I jokingly told her she had planted them in the wrong place — she should try New Jersey or Minnesota.
She loved hosta's oversized, dramatic foliage, but in our climate where watering should be limited, it suffers in dry air and without constant moisture around roots. Like many other non-native, large-leaved species — Rodgersia, Gunnera, Caladium, Ligularia — ample water is essential for opulent, dramatic, super-sized foliage.
Instead, consider Phlomis russeliana, native to the Mediterranean basin. Its foliage texture and flowering habit is completely different, but its low mound of broad, evergreen, heart-shaped foliage is a welcome presence year-round with minimal irrigation. In late spring, flower stalks stand tall sporting whorled yellow blossoms that remain good-looking for weeks, even after turning rich brown.
Phlomis russeliana takes either sun or light shade, spreads slowly, and needs only an annual clean-up in fall to remove bloom stalks and faded foliage. Luxuriant new leaves appear before the old are cleared away.
For a more massive display that contrasts with low shrubs and small foliage, plant oakleaf hydrangea (Hydrangea quercifolia). Frothy, creamy white panicles in spring and summer are upstaged on this shrub by large green, deeply lobed leaves that morph into glowing orange, red, and burgundy tones in autumn. In light shade, only infrequent summer watering is needed.
Planting under trees
If we could ask them, most trees would say they prefer a circle of mulch to keep weeds at bay, their roots cool, and a dry zone around the trunk. But many homeowners like to see some decoration beneath the canopy and often keep the dry zone too moist for the tree's optimal health and longevity.
The most common treatment is lawn, which always demands water to look its best. But impatiens, azaleas, and other bright points of bloom requiring constant moisture are frequently planted.
There are options for planting in dry shade under trees, especially under our native oaks that do not tolerate moist soils in summer.
Dry shade strikes many gardeners as an unfortunate condition; yet, there are many lovely plants that thrive there with little or no summer watering. Cyclamen blooms for months during the rainy season, ablaze in bright red or more sedate in pink or white. Lily turf (Liriope), particularly variegated forms, brighten shaded sights year-round.
Though Epimedium can be found in our nurseries, it isn't often planted despite being extremely tolerant of dry shade. Some forms are called bishop's hat for the shape of their pert white or pinkish blooms. Others are yellow, often with red tints.
Vinca and ivy (Hedera) are often suggested, but to avoid their invasive tendencies, forego both and opt instead for a Sonoma County native, yerba buena (Satureja douglasii).
Yerba buena extends long, thin stems cloaked with bright green foliage. Tiny white flowers bloom in spring and summer. Trim stems to keep this groundcover from spreading too far. Leaves can be dried and used for tea.
Rosemary McCreary, a Sonoma County gardener, gardening teacher and author, writes the monthly Homegrown column for The Press Democrat. Write to her at P.O. Box 910, Santa Rosa, 95402; or send fax to 664-9476.
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