Water Wise Plants

The only maintenance this plant needs is to cut back the inflorescence after the flowers have dropped off. Aloe striata is also easy to propagate. Remove the pups (baby plants) from the base of the plant, let the stems dry and harden, and then plant the cuttings in a pot of cactus soil mix.

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.

PADG notes: ‘Seafoam’ has been used as a small edging plant in the Demonstration Garden. We have repeated silver foliage plants around the edge of the garden beds as a way of tying different beds together. But we find cutting off the flowers to keep the plant looking good to be labor intensive. 

Given enough water from late fall through spring, intermediate bearded iris can grow to a height of 2.5 feet tall, and tall bearded iris can reach 4 feet in height. With enough water they develop tall flower stalks supporting numerous large blooms. With less water during the growing season, the plants are smaller with fewer flowers, but the blooms are still striking. Improve growth by adding compost and mulch in the fall, which helps retain soil moisture and provides nutrients for better bloom. Allow plant leaves and soil to dry out between watering to prevent fungal infections and flower loss.

During the summer, bearded irises are dormant, and their leaves die back. For aesthetics many people cut the leaves back when they begin to yellow, but it is not necessary. Plants remain healthy with and without summer trims. Be aware though, there is one major maintenance issue when growing bearded iris. These plants grow from thick rhizomes. Each year new rhizomes spread from the original making a larger clump. As the older rhizomes die, a dead spot will eventually appear in the center of the iris clump. To prevent this from happening and to keep clump size in check, divide iris rhizomes about every three years. Do this during the hot summer months when plants are dormant and fungal infections are less likely to affect the cuts from the mother rhizomes.

PADG notes: Several varieties of Ceanothus were planted several years ago in the Native Bed at the Palo Alto Demonstration Garden. As of 2022, Ceanothus maritimus ‘Valley Violet’ is doing the best in the group. It is very drought tolerant and is living up to its All-Star status with the garden’s dry season irrigation cycle. Established plants are watered once every three weeks with drip lines.

PADG notes: This plant tended to die within two years in the Demonstration Garden’s regularly watered clay soil. The rockrose was planted on a berm (small hill) and received minimal summer water.

Also, the shrub requires no deadheading or pruning, so it is practically maintenance-free. Look for some of the newer cultivars of Correa that have been bred to produce more visible flowers above the foliage.

Echeverias are sometimes called ‘Hen and Chicks’, but so are Sempervivums, another succulent. It's one of the problems with using common names. In this case, it is better to use the botanical name, Echeveria.

PADG Notes: Echeveria ‘Imbricata’, a UC Davis Arboretum All-Star, is featured in the Demonstration Garden. Some Echeverias do well in full sun, but Imbricata seems to do better in half shade and with a drip very close to the roots.

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.

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.

Take care when cutting Euphorbias because the milky sap can be very irritating to the skin.

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. 

The Grevillea pictured is a dwarf form of Grevillea rosmarinifolia. It has evergreen rosemary-like leaves and stays about 3 feet high by 6 feet wide. It flowers in the winter when not much is blooming and provides a tidy, low growing shrub in the summer when other plants take center stage.

Grevillea does well with a deep watering once every three weeks. It also grows well in gardens that get regular water. Be careful of using fertilizer with phosphorus around Grevillea. No maintenance, deadheading, or trimming back is required for this plant.

Note that there are over 250 species and hybrids of Grevillea. Some have fine leaves; others have courser leaves. Some make great ground covers; others grow to be the size of the small trees. Some tolerate cold weather better than others. Research cultivars carefully before selecting plants.

Helianthemum likes full sun and well-draining soil with low to moderate water. Shear off the dead flowers to encourage repeat blooms.

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.

PADG notes: Some reference books say this plant can get up to 6 feet tall, but in the Palo Alto Demonstration Garden, they have stayed a modest 3 feet tall and wide. The trick may be not to overwater them.

Occasional water will encourage repeat blooms. However, Phlomis fruticosa will tolerate very dry conditions. This plant can be cut back by half in the fall to keep it compact. Some Master Gardeners are a little more daring and like to cut Phlomis back to six inches above the ground. This will keep the plant even more compact. Another option is to do nothing at all if the size and woodiness of the plant are not an issue.

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.

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: 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.

PADG Notes: A drawback to Bush Germander is it can grow to be very large. We pruned ours back to 4 inches to help control its size. The shrub came roaring back with a natural shape and a slightly smaller size. The winter blooms are plentiful. We recently planted a smaller Teucrium cultivar, 'Compactum' that is reputed to stay 3 feet tall and wide and have intense blue flowers.

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.

Thyme makes a nice ground cover for small spaces. It has grey-green leaves and small white flowers.

PADG Notes: To keep thyme neat, the faded flowers are sheared back in early spring. Many thymes are not long lived, but Thymus vulgaris has proven to be long-lived in our water wise garden.

PADG Notes: This is a summer dormant plant, which means it can get by on almost no water in the summer but has unattractive leaves starting in July. We solve the ugly leaf problem by cutting the leaves back to a couple inches above ground in mid-summer. This results in a bare spot in the bed. If that bothers you, install a plant next to the Watsonia that will fill in the bare spot during the summer and fall months.

Westringia grow into large plants so plan ahead or be prepared for a lot of pruning. Unlike rosemary, the stems of Westringia do not get woody, which makes it is a better long term landscaping choice.