Water Wise Plants

Greek yarrow doesn't need a great deal of maintenance. To encourage reblooming, deadhead it regularly. This plant will spread, so don't plant it too tightly.

PADG notes: This unnamed cultivar of Agastache has been a mixed success in our gardens.

PADG notes: This specimen is planted where it gets morning sun and afternoon shade so it needs less water than recommended. During hot, summer periods, the plant is hosed weekly in addition to a once every three-week drip irrigation cycle.

PADG notes: Our Aquilegia eximia planted in partial sun hasn't done as well as we would like. We are trying it in a shady spot. The plant may need more water than our water wise garden is given.

To keep Arctotis looking its best, the flowers should be regularly deadheaded when past their prime, and the plant should be replaced every few years. Cuttings root easily in the cool months.

PADG notes: The Palo Alto Demonstration garden has planted ‘Purple Torch’ throughout the beds to unify the garden. It combines well with Bulbine frutescens, which blooms at approximately the same time.

California aster looks best if regularly deadheaded. After it is done blooming in the fall, shear it back to the ground to keep a tidy look in the garden. The plant will cheerfully return when winter is over.

PADG notes: California aster spread very rapidly even without supplemental water. It might work better in a situation where a rapidly spreading plant is needed for erosion control rather than in a small, mixed perennial bed.

Sunset’s Western Garden Book suggests shearing before spring growth. The stems on these plants can become woody.

Echinacea purpurea is a green-leaved perennial that produces large purple, daisy-like blooms in the summer. It can grow to four feet in height and works well in the background of garden borders. It needs minimal drip irrigation, dies down after bloom, and resprouts in the spring with little extra maintenance required.

Even with minimal water and no fertilizer, these plants need staking. Supports put in place in the early spring are quickly covered with foliage and hidden from view. To encourage new blooms and keep the plant looking fresh, remove the entire flowering stalk.

PADG notes: Our experience with Erigeron 'Wayne Roderick' has been very good, although we have noticed that the foliage burns in the summer unless given more frequent water.

Happy in sun or part shade, these plants prefer good drainage. With supplemental water, you can expect some repeat bloom all summer. Mimulus is a favorite in native plant gardens because of its color range.

When new foliage appears at its base in late winter, the plant is ready to be pruned back to the new green growth. This hard pruning will rejuvenate the plant. If there is no growth at the base, then gently pinch the tips to encourage new growth. The scientific name of this plant was recently changed from Mimulus guttatus to Erythranthe guttata.

PADG notes: Some Master Gardeners have found this plant to be short-lived; other Master Gardeners have Mimulus plants in their personal gardens that are over five years old and doing just fine. These plants are easy to propagate from cuttings and seeds.

California poppies look great in wild areas and are lovely massed. They make excellent temporary fillers in new beds and landscapes. 

California poppies can get by with almost no summer water, but they tend to look shabby and weedy under these conditions. To encourage continuous bloom, provide moderate amounts of water and trim the plants back to almost ground level when the foliage turns grey, and the plants lose their flowers.

Although California poppies are perennials in the Santa Clara Valley, they can be treated as annuals. California poppies can be problematic because they are aggressive reseeders. They should be heavily thinned even in desired areas and removed entirely when undesired. They can reach one and a half feet wide in size and can smother other plants.

Most retail nurseries and many hardware stores sell seeds for California poppies. Some mail order companies are good sources for some of the less common varieties of these California natives. Plant seeds in the fall for a spring show. Be sure to cover seeds with mulch to hide them from the birds and water regularly until they sprout if the winter rains have not arrived.

Euphorbias can be aggressive reseeders so cut off the flower stalks at the base sometime in May before they set seed. Be careful of the sap as it may irritate the skin. 

Heuchera ‘Rosada’ prefers light shade and occasional to moderate water. With beautiful rosettes of low growing foliage and stalks of pink blooms, it is a favorite of woodland gardens. Removing the flower stalks when the plant finishes blooming is all the maintenance needed. Although these plants will grow in full sun, they will need more water to look their best. Plants grown in the shade can tolerate less water.

UC Davis Arboretum selected Heuchera ‘Rosada’ for its Arboretum All-Stars designation, which identifies plants that are easy to grow, reliable, do not need a lot of water, and have few pest or disease problems.

PADG notes: In the Water Wise Garden, several Heuchera maxima are growing in a shady spot where the soil is quite rich. These plants have grown very large and are stunning in the spring when they bloom.

Deadhead the plants when the old flower spikes become unattractive. When the leaves start looking shabby in the winter, cut the foliage back about three inches above the ground. Kniphofia will come back beautifully in the spring. The plant divides easily but it doesn't seem to require dividing to stay vigorous.

PADG notes: The Palo Alto Demonstration Garden has several Kniphofias including ‘Christmas Cheer', which is a UC Davis Arboretum All-Star. It has brilliant orange buds that open to a deep-gold tubular flower. ‘Christmas Cheer’ blooms in the fall and winter unlike many other Kniphofias.

The big drawback to Linaria is that it reseeds. The seedlings are easy to spot and pull out. If you deadhead the flowers and mulch your soil regularly you will cut down on the amount of reseeding.

PADG Notes: After frost damage, scraggly branches are pruned back to about three feet for a neater appearance. When danger of frost is gone, the plant is pruned to the ground. Mexican lobelia has spread aggressively in the garden and needs regular root pruning to keep under control.  

Warning: Lobelia may cause serious illness or death if eaten. If ingested, immediately call the Poison Control Center or your doctor. In addition, the juice or sap of the plant can cause a skin rash or irritation. Wash the affected area of skin with soap and water as soon as possible after contact.

Herbs are also great for attracting beneficial insects to gardens. And the less they are watered, the more intense the flavor.

Many oreganos benefit from being sheared to the ground in the fall. Harvest oregano any time for cooking, but the most intense flavor is just before the plants bloom.

This is a geranium that thrives in low water situations and in full sun. It can also do well in part shade with generous water. This cultivar seems to be more cold hardy than other Pelargonium. The only regular maintenance it needs is occasional deadheading.

Some Phormiums revert to the brownish color of the species after several years. 'Amazing Red' has held its color in the demonstration garden for six years and for ten years in some Master Gardeners' personal gardens.

To maintain, prune out dead leaves at their base, but don't try to reduce size of Phormiums by cutting back the leaves. Unlike grasses, Phormium leaves won't grow back, leaving stubby unattractive leaves.

PADG notes: Though it is supposed to be small, in the demonstration garden this plant has grown to about 3 feet high and wide in six years, larger than expected. The plant has not bloomed.

The pale-yellow flowers of 'Happenstance' provide a calming contrast to more brightly colored flowers. The arching branches of 'Happenstance' rose form a neat mound.

PADG Notes: This rose is a slow grower in the garden and doesn't need a lot of deadheading or pruning because it is not highly fertilized or watered. In February, some of the longer canes of 'Happenstance' are pruned back to about two feet to keep the rose a three-foot mounding shrub over the summer.

Despite the low maintenance approach, this plant blooms continually in the spring, summer, and fall. It is highly recommended as a medium-sized rose for water-wise perennial gardens.

This attractive plant has silver leaves and bright blue flowers. Deadheading will encourage the flowers to come back in the fall. Shearing back to the ground in late fall rejuvenates the plant.

The flower pictured here is Salvia hybrid 'Cristine Yeo'. It is a cross between Salvia microphylla and Salvia chamaedryoides.

PADG Notes: Salvia microphyllas prefer full sun, but this plant is doing well with morning sun and afternoon shade in our garden. It seems a little floppy, which might be a shade issue or just its natural form. 

With a little work, the  Salvia microphyllas can be kept in top form in your garden. At PADG, all flowers are sheared off in early summer and again during fall clean up. This keeps the plant more compact and encourages repeat blooming. In the spring, one third of is oldest stems are pruned out to keep the plant from getting woody. A nice bonus for pruning work -- the leaves of these Salvias smell wonderful.

In the fall, the skinny branches of this plant are sheared off to form a neat ball. Avoid cutting into the thicker woody stems because it could affect regrowth. Regular pruning keeps this plant fuller and encourages more flowering the next season. If you want to learn more about Salvias, we suggest reading Betsy Clebsch's book called The New Book of Salvias.

The plant spreads by underground rhizomes and can eventually cover a large area. Hummingbird sage can make a colorful ground cover in dry, shady conditions.

From spring until fall, flowering stems appear above the foliage. The flower clusters are spaced evenly along the stems creating a bold vertical accent. Light pruning after blooming will help keep this plant neat.

PADG Notes: In the PADG Water Wise Garden, we found that too much summer sun burned the leaves and made the plant unattractive. Also, our hummingbird sage spread more aggressively than had been anticipated. A few runners were replanted to shadier spots under oak trees and will be monitored carefully. 

PADG Notes: We originally had a full sized Santolina, but the plant fell apart when it bloomed. It was unattractive, so it was removed it from the garden. Santolina chamaecyparissus 'Nana' is a good choice for an edger or in a knot garden because it doesn't require the pruning that the larger species needs. We've used short silver plants as edging throughout the Demonstration Garden to tie the garden together visually.

PADG Notes: When Sisyrinchium bellum dies back with hot weather, the dried foliage is removed. With additional water throughout the summer, plants will stay evergreen and continue to occasionally rebloom. Some reseeding will occur, but not aggressively.

PADG Notes: Mexican Bush Marigold can become large and ungainly, so we recommend shearing this plant several inches from the ground in the spring to keep the plant compact and give it a nice shape. Also, prune out any frost damage once the danger of frost is over.

Tagetes lemmonii is not long-lived in the garden, but if you like yellow flowers and enjoy the smell of its leaves this plant is worth planting. In the demonstration garden we removed Tagetes lemmonii because it repeatedly suffered frost damage and was not attractive.

Meadow Rue is used in woodland and shade gardens as a perennial background plant. It has beautiful lacy blue-green foliage that unfurls from purplish shoots. The tiny unisexual flowers are produced atop 2 - 4 ft. tall stalks on separate plants. The male flowers are showier with dangling cream-yellow colored stamens; the female flowers are clusters of greenish pistils. It goes dormant in late summer when it is allowed to go dry. This Meadow Rue is easy to grow, in part sun to shade. It grows with occasional to regular irrigation, and can be drought-tolerant once established.

This is a fast-growing plant, which if happy in the garden, will spread by seed. It has a small clump of green leaves that produce tall flowering stems in the hot summer months. The overall look is light and airy. Tall stems should be cut down when flowers have faded.

PADG Notes: This plant is no longer in the garden because it needed some supplemental water to keep it thriving.