Water Wise Plants

The tree produces a large nut that resembles a buck's eye, thus the name. The nut is poisonous to eat. The nuts easily reseed where they fall, so collect them if new sprouts are not desired.

Without summer leaves, the pale bark of the California buckeye offers interest and structure in the garden and is very easy to prune and shape.

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: To prevent accidental injuries, we prune off the sharp spiky tips of this plant.

It’s a striking plant with an interesting form – it almost looks like a piece of modern sculpture. Spider aloe is frost-tender so be sure to protect it on cold winter nights.

PADG notes: In the winter, spider aloe is rumored to have red flower spikes that are attractive to hummingbirds. Unfortunately, this cannot be confirmed because the plant has never bloomed in our location.

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.

PADG notes: The tree was planted at PADG in 2020. It is currently doing well and is drip irrigated every two weeks during the dry season. As it matures it will need less water.

‘Emerald Carpet’ is a slow growing California native manzanita from the coast of Mendocino County. It is a very attractive plant with dark glossy leaves, reddish stems and small flowers in the early spring.

There are many different cultivars of manzanita, ranging from ground covers to small trees. Manzanitas are a good wildlife plant and typically are a hearty plant. They do well in very dry situations. Most manzanitas need superb drainage, or they will struggle and die. Plant on a mound or slope and water weekly for the first summer and less after that. By the third summer, stop watering. Avoid fertilizing the plant.

These plants rarely need pruning. Remove the odd branch that dies back in the late summer and the plant will fill in. Some gardeners will remove the lower branches on some of the larger manzanitas to highlight the interesting branching structure and reddish bark. Some Santa Clara Master Gardeners have had success using the cultivar ‘Carmel Sur’ as a ground cover in low-water landscapes.

PADG notes: ‘Emerald Carpet’ has not thrived at PADG. It may need more water than most manzanitas.

If the tips of Arctostaphylos branches are pruned, this large shrub will become very dense and make a good privacy screen. Removing the interior stems and leaves instead exposes the interesting red bark. The latter is a good approach for making the shrub more of a focal point instead of a background plant.

PADG notes: PADG planted three ‘Howard McMinn’ manzanitas at the entrance of the Water Wise Garden. They have struggled there over the years, damaged by foot traffic and the occasional joy rider.

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. 

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.

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.

PAGD notes: In our original planting, three pygmy barberries were planted along the front bed. Unfortunately, only one plant survived, but it is doing well. Barberries are slow growing plants and it took a while for them to get established in the garden. More frequent watering would have benefited these plants.

The compact size, bright green leaves and blue springtime flowers of Borago officinalis provide a nice contrast to the darker and more muted greens of most water wise plants. Borage is an annual that dies back without supplemental water in summer. It reseeds readily, allowing new plants to spring up in random places. Plants are easy to remove when they begin to die back or if the seedlings come up in undesirable locations. The plant is edible and its star-shaped blue flowers taste like cucumber. In a low water situation, the plants seldom grow over 1.5 feet.

This South African native is a great plant to mix into a low water flower border. It is evergreen, has spikes of star-shaped yellow or orange flowers and cool fleshy pencil-shaped leaves.

The yellow-flowered Bulbine frutescens blooms mostly in the winter when very few plants are in flower. The cultivars ‘Hallmark’ and ‘Tiny Tangerine’ are more compact, have orange flowers, and bloom in the summer. Though the plant looks best when watered several times a summer, bulbine can survive on less water.

When bulbine starts to flop open in the center, it is time to dig up and start fresh by planting a piece of the original plant. Cuttings will grow without much special treatment: stick them in the ground and wait for a new plant. The best time to start a new plant is during the rainy season.

PADG notes: We have used two plants to mark an entryway to the garden.

Callistemon are very adaptable plants for Santa Clara Valley gardens and are attractive to hummingbirds. The many cultivars of Callistemon range from tree-size to shrub-size to ground cover height.

PADG notes: The Callistemon is pruned and shaped to a shrub and is has been planted next to Miscanthus sinensis ‘Yaku Jima’ as seen in the photo.

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

This plant was once considered a California native, but that has recently been disproven. The new name is Carex divulsa, but it may still be sold in nurseries as Carex tumulicola.

PADG notes: At the end of winter, many people cut this plant back to several inches above the ground, but that has not been necessary at the demonstration garden. Because plants are in the shade, they don’t become tattered. Reseeding has also not been a problem, probably because of extensive bark mulch and drip irrigation in the water wise garden.

Carpenteria californica is a flexible plant, tolerating light to moderate water and full sun to partial shade. One drawback of this plant is the brown leaves don’t always drop off in summer. If this shrub is in a very visible spot, it may be desirable to cut off the brown leaves for a cleaner appearance.

There are many different kinds of Ceanothus. Some are low growing ground covers; some are shrubs, and some become tree-like. Most Ceanothus need to be planted in a dry part of the garden because they are very sensitive to summer watering. Ceanothus varieties originally from the coast, such as ‘Carmel Creeper’, are more tolerant of summer water. Cultivars should be researched carefully to select the right plant that meets individual garden conditions. 

It is best to prune Ceanothus in the late summer when they are dormant. Take care not to cut into large branches. Only prune branches that are an inch or less in size.

Even with proper pruning and watering, these plants can be short-lived (five to ten years), but their beautiful spring flowers more than make up for any challenges.

‘Concha’ is one of the best Ceanothus cultivars for Santa Clara County. It is more adaptable to typical garden environments than many other Ceanothus, tolerating heavy clay soil, drought, or summer watering. Overwatering will shorten the life of any Ceanothus so be sure to allow the soil to dry between waterings.

PADG notes: Online photos show a plant covered with pink flowers but that hasn’t been the case at the Demonstration Garden. The flowers have been pretty but sparse and the plant does not look vigorous. It has been in the garden for several years and is still a non-performer. We can’t recommend this plant for low water gardens in the Palo Alto area.

Like many natives, this plant needs good drainage, so consider planting it on a mound. Avoid summer water. Cercis can be pruned over the winter to open up the branching structure to give the plant a more tree-like appearance.

PADG notes: This slow growing plant has not had problems with pests or diseases. We have pruned this Cercocarpus to have a more open form, so it is now a very attractive, airy shrub.

For best flowering, corms should be divided every two to three years. Be aware that the plant will reseed vigorously, particularly Chasmanthe aethiopica, so be sure to deadhead the flowers if this is not desired.

PADG notes: We also tried Juncus, a similar looking plant, but found it did not do well with once every three weeks watering.

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.

Like Correa ‘Dusky Bells’, Correa alba thrives in sun, partial sun, or shade; is deer resistant and bird friendly; and has long-lasting flowers. The plant does well with moderate to occasional water, tolerates alkaline soil, and is evergreen. The plant is sensitive to overwatering and overfertilizing.

PADG notes: Some find Correas to be short-lived but at the Palo Alto Demonstration Garden, this plant is still going strong after several years in the garden. The beds in garden are mulched with wood chips, but not fertilized and watered deeply with drip irrigation once every three weeks.

Like many succulents, Cotyledon orbiculata is easily propagated from cuttings and does well in containers. It is cold hardy to 20–25°F.

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.

Cut California fuchsias back to one inch stubs in the fall or winter. For varieties that tend to ranginess, pinching the outer tips in late May or June will encourage them to be denser and less floppy.

California fuchsias are drought tolerant and can be completely summer dry, but will be lusher if given a once a month deep watering.

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.

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. 

This grass needs occasional water and good drainage. It tends to brown out in the middle, but can be divided and replanted to renew it. In a low water garden, these grasses seem to hold their blue green color better in the shade.

Be aware that geranium ‘Biokovo’ can become aggressive and spread quickly if planted in soil that is fertilized and watered regularly. 

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.

It is a member of the rose family, producing small white flowers in early spring followed by showy red berries. The berries remain on the shrub for several months while they slowly ripen. Once ripe, they attract many different species of hungry, grateful birds.

Young toyons may take a few years to settle into the garden but once established, they are easy to grow and can be pruned to manage their size or to keep them looking fresh.

PADG notes: The toyon in the Palo Alto Demo Garden Water Wise Garden was planted in the winter of 2008 from a one-gallon container in a spot where it gets afternoon shade. This toyon is still a modest sized shrub many years after planting.

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.

Spent flowers can be sheared off when the plant is done blooming. It is easy to start new plants by planting cuttings directly into the soil when the weather has cooled.

Master Gardeners have found that Pacific Coast irises seem to prefer part shade and low to moderate water. Native irises are useful under oaks, in woodland gardens, and in meadows.

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.

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.

From a design perspective, the delicate foliage and showy plumes of Miscanthus add movement and texture to the garden. The plumes look especially lovely in the fall afternoon light.

To keep a fresh look, cut Miscanthus to the ground in winter and divide every few years. That is the only maintenance needed for these trouble-free plants. Miscanthus sometimes takes a year or so to get established.

PADG Notes: Miscanthus 'Yaku Jima' is a favorite of Roberta Barnes, one of the founders of the Palo Alto Water Wise Demonstration Garden. She has found Miscanthus to be one of the best-looking grasses for full sun and low water. There have not been any problems with this grass reseeding in the Demonstration Garden. 

This plant can be hard to find, but is well worth requesting from a nursery as a special order.

PADG Notes: This grass is extremely low maintenance and unlike many other grasses doesn't need to be divided every couple years. To keep this grass attractive, the old foliage is raked out to make room for the green spring growth. 

Muhlenbergia rigens is a reliably pretty California native grass. The flower stalks are persistent and look attractive year-round. The UC Davis Arboretum, which has selected Muhlenbergia as one of their "All Stars", suggests using it as a low informal screen.

Muhlenbergia requires very little maintenance. UC Davis recommends shearing Muhlenbergia a couple inches above the ground in the early spring every three years to encourage new green growth. California Native Plants for the Garden suggests periodically raking out dead foliage with a fan rake. Otherwise, this is a maintenance-free plant.

PADG notes: This plant is used as an accent plant in both the native and non-native garden beds with good results. PADG Garden also grows Muhlenbergia dubia, a smaller cultivar. This is an attractive low-water plant, although the UC Davis Arboretum suggests giving M. dubia slightly more water than M. rigens.

After the first set of blooms finishes, catmint should be cut back several inches to keep it from getting leggy and encourage another set of blooms. This is a fun job because the leaves have a wonderful smell. Be aware that some cats also love the smell of the plant and will roll their bodies in the plant and flatten it.

PADG Notes: Catmint was one of the earliest plants in the Demonstration Garden providing much needed color the first summer. It is used extensively to visually tie the beds together.

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.

Cut back Polygala to about 10 inches above the ground in late winter to maintain its compact shape.

Sunset’s Western Garden Book recommends providing regular water for Polygala. Several Master Gardeners have not found Polygala fruticosa to be long-lived in their home gardens.

There are many different varieties of coffeeberry. They can be used as an informal hedge or screen or gently pruned to be a bedding or foundation shrub. 'Mound San Bruno' has a compact growing habit that works well in a perennial bed.

PADG notes: The California native coffeeberry 'Mound San Bruno' was planted in a native plant bed that receives both sun and shade. The amount of sun the bed gets varies depending on the time of year and time of day. That's a common condition in many gardens and not all shrubs do well in both sun and shade.

The coffeeberry was watered once a week to get it started, but now that it is established, it is only watered once or twice over the summer to wash the dust off the leaves.

This plant is more of a garden workhouse rather than a star, but a garden full of stars would be overwhelming. These are good background shrubs for places that get no irrigation. The flower bracts, which appears in the fall, are red and show up well against the shiny green leaves. The flowers appear several months later and are small and white.

This plant can be used as a focal plant in the garden surrounded by smaller perennials or as an understory plant when combined with large trees with low water usage, like California Oaks. It can get by with very little water but looks fuller when a moderate amount of water is applied in the summer. When using Ribes under a California Oak, avoid summer water.

There are many different cultivars of Ribes available with flowers ranging from red to pink to yellow to white. Some types of Ribes work well in full sun.

Hummingbirds are attracted to the flowers, especially since they bloom when not much else is flowering. In the fall the shrub has blue-black berries that attract fruit-eating birds including mockingbirds and cedar waxwings. Ribes sanguineum is found along the Pacific coast from California to British Columbia, Canada.

Because of the spiny branches, this shrub should be kept away from walks. It makes a formidable barrier.

Rosa 'Mutabilis' grows into a large shrub with delicate blossoms that open orange, then turn pink and finally maroon as it ages. The bronzy colored new foliage is also attractive. Blooming all summer, it is a focal point in the garden.

PADG Notes: This rose is pruned back to about four feet in February, selectively cutting smaller branches back to a main stem. This helps keep the plant a manageable size and encourages lots of blooms over the summer.

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.

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: In the demonstration garden, Sedum 'Autumn Joy' is planted in a very rocky, well drained spot. It has grown very slowly, but steadily. It is a favorite of many gardeners because of the long-lasting fall color.

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.

"Helen von Stein' is a wonderful cultivar because it has extra-large leaves and doesn't bloom a lot. With its large leaves, it provides contrast to smaller leaved plants in the garden. 

After a couple years, these plants tend to spread and die out in the middle. Use a sharp shovel and divide the clumps in fall or early winter. Lamb's ears may also have some die back over the winter; we recommend leaving the dead leaves in place until all danger of frost has passed.  

PADG Notes: We have used Stachys and other silver-leaved plants to visually tie together the edges of our beds. Some gardeners love the dramatic flower spikes on lamb's ears, but we have mixed feelings. Sometimes we cut them off and sometimes we leave them in place.

One of the best features of snowberry is it does well in dry woodland conditions. It is a rare shrub that will thrive under a thicket of oak trees.

Some people find the branching structure of snowberry to be messy. California Native Plants for the Garden recommends occasional coppicing to improve its appearance. Coppicing means to cut back a plant to about one foot from the ground. This usually works best right before a plant puts out new growth in the spring.

PADG Notes: Our snowberries grow in a shady area that gets no summer irrigation.

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: This plant is used as an edger in one of our beds. One drawback to the plant is the small yellow flowers that appear in late spring. Some people like them, but we cut them off.

This plant has survived, but not thrived at in the Palo Alto Demonstration Garden. One reason might be that it likes more water than it receives. It is watered deeply every three weeks. We suspect this plant would look lusher in the summer with deep weekly watering.

This plant is not easy to find in nurseries and gardens, but if you like the texture, Tanacetum densum amani is worth seeking out.

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: 'Queen Fabiola' has been planted in several beds on the edge of the garden that receive limited or no supplemental water. Because 'Queen Fabiola' has delicate flowers and blooms in the late spring when lots is going on in the garden, this bulb needs to be massed to make an impact.

Avoid summer water especially in clay soil. We remove the brown leaves in the summer to keep a tidy look, but that's not necessary.