Choosing shrubs to use less water

Written for the Davis Enterprise, November 25, 2011

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This month we continue our theme of reducing water use in the landscape. It is estimated that 80% of residential water use goes to yard watering.

Last month's (October 2011) column focused on water use by lawns.


To recap:

* reduce total square footage of grass;

* plant seed of grass species that can use less water, such as fine fescues;

* replace some lawn areas with lower-water ground covers.

This month I'm going to focus on shrubs that make the backbone of the yard, providing privacy, attractive foliage, and seasonal flowers. Aesthetically, it is best to repeat one type, rather than having a hodge-podge of mixed foliage, and then add some of the others for contrast. If you have existing shrubs, interplant some of these listed, do some careful pruning for a couple of years, and then remove the more water-intensive types after the new ones grow up a bit.

What about your existing shrubs?

We see a lot of plants with problems resulting from watering too often, so just by watering correctly you can reduce your water bills and have a healthier landscape. Water slowly, deeply, and infrequently. When we ask about watering schedules, it is common to learn that shrubs are being watered 3 to 4 times a week. That's too often! And they're being watered for ten or fifteen minutes. That's not long enough!

Did you know that many or most of your landscape shrubs could go a week or more between waterings if you irrigate deeply enough each time? Many can go much of the summer on just a few deep irrigations, and some need no summer water at all!

Careful plant selection is another approach to reducing your water bill.

Choose trees, shrubs, and flowering plants that can live with reduced watering.

Here is a list of some shrubs that could be watered as little as once a month once established (which means after the first summer). Some require drought: California natives are sensitive to crown rot if watered too often. The others can be watered more often if necessary. All are evergreen unless noted as deciduous.

* Botanical name: Buddleia davidii

Common name: Butterfly bush

Butterfly bushes love sun, attract butterflies and hummingbirds, and bloom all spring and summer. There are many varieties, ranging from 6 feet to more than ten feet tall, with purple, pink, violet, or white flowers.

* Callistemon citrinus

Bottlebrush

Fast-growing, somewhat open growth habit benefits from pinching and shaping. Showy red flowers, off and on through the year, attract hummingbirds. Prone to iron chlorosis when irrigated.

* Chaenomeles japonica

Flowering quince

The first shrub to bloom in the late winter! Some stay under 3 feet; several varieties grow to 5 - 6 feet or more. Fruit, if any develops, makes unique, aromatic jelly. There are white, pink, orange, and red varieties. Deciduous.

* Dodonea viscosa 'Purpurea'

Purple hopseed bush

Fast-growing quick screen. Bronze foliage turns dark purple, almost maroon, in winter. Fairly open habit, but can be sheared for greater density.

* Eleagnus x ebbingei 'Gilt Edge'

Elaeagnus

Upright growth habit, thornless. Silvery leaves with bright golden margins. Flowers attract beneficial insects; edible fruit attracts songbirds.

* Escallonia rubra

Red escallonia

Big shrub with dark, glossy green leaves and dark red flowers. Leaves have a resinous odor. Flowers attract hummingbirds.

* Garrya elliptica

Coast silktassel

Dark green foliage on a large, dense shrub. Long tassels of flowers in late winter are interesting and attractive. 'James Roof' is a shorter, more compact variety than the species. This California native is best unirrigated.

* Grevillea species and varieties

Australian natives that have odd-shaped, showy pink or red flowers over a long season. All attract hummingbirds. There are dozens of varieties; check descriptions for winter hardiness in our area.

* Heteromeles arbutifolia

Toyon

Grows 2 to 3 feet a year, eventually more than ten feet tall. Flowers are very attractive to beneficial insects. Beautiful shiny red fruit hangs on into winter, attracts birds. There is a yellow-berried variety called Putah Gold, introduced by the Arboretum. This California native is best unirrigated.

* Lavatera maritima

Tree mallow

Also sold as L. bicolor. Fast grower. Gawky growth habit--shear it occasionally, or prune it back severely in the spring or fall. Flowers are light pink with dark rose veins. Blooms all summer.

* Rhamnus alaternus

Italian buckthorn

Fast-growing, upright, with dark shiny green, dense foliage. Flowers attract beneficial insects; small berries (you don't see them) attract songbirds. Great for a quick hedge for privacy. Don't overwater. The selected form John Edwards is more resistant to crown rot. Variegata has cream-variegated leaves, is slower growing and smaller.

* Rhamnus californica

Coffeeberry

Slow-growing native cousin of the buckthorn that looks very much like Toyon (Heteromeles), with similar, larger red berries in winter. Variety called Leatherleaf has larger, darker leaves. This California native is best unirrigated.

* Xylosma congestum

Shiny xylosma

One of the toughest landscape shrubs around. Tolerates heat, even reflected off a west wall; drought; shade. Can be trained into a beautiful small tree, clipped as a formal hedge, or trimmed for an informal screen.

Some plants usually grown as trees can be grown and pruned as shrubs.

* Arbutus unedo 'Compacta'

Strawberry tree

Showy flowers and fruit, beautiful bark like madrone. Fruit litter may be a problem, but it is edible and birds like it. Heat and drought tolerant. Grows 1 - 2 feet a year. Easily kept at 6 to 8 feet with one annual pruning.

* Ceanothus 'Ray Hartman'

Wild lilac

This variety grows to 10 - 15 feet or more. Attractive, large shiny leaves. Pretty medium blue flowers in large clusters in spring. Water deeply and very infrequently in summer.

* Citrus hybrids and varieties

Many varieties make excellent patio or container trees, or can be clipped as shrubs. Meyer lemons, kumquats, and satsuma mandarins are naturally dwarf. Minneola tangelo is especially attractive.

* Cotinus coggygria 'Royal Purple'

Purple Smoke tree

Purple leaves and purple flowers make a striking contrast with grey or glossy-leaved plants. Very tolerant of drought and heat. Gets iron chlorosis if irrigated heavily. Deciduous.

* Feijoa sellowiana

Pineapple guava

Plant named varieties if you want reliable fruit production. Edible flowers! Very drought tolerant. Fuzzy grey-green leaves make a nice contrast with red-leaved or shiny-leaved shrubs.

* Junipers:

Juniperus chinensis 'Torulosa' (also called 'Kaizuka')

Hollywood juniper

Striking, contorted upright growing juniper with dark green foliage. Excellent specimen plant. Very tough, drought-tolerant.


Juniperus scopulorum 'Gray Gleam'

Gray Gleam juniper

Other varieties of this species (Cologreen, Pyramidalis, Blue Haven) have similar growth habits. These are all pyramidal-shaped, upright growers useful in formal plantings. Wichita Blue is more cone-shaped. Very tough, drought-tolerant.


Juniperus virginiana 'Skyrocket'

Skyrocket juniper

Upright column like an Italian cypress. Useful for a formal effect in smaller gardens. Very tough, drought-tolerant.

* Laurus nobilis

Grecian Bay laurel

The bay leaf used in cooking. Very versatile garden plant. Large shrub, eventually growing to 30 feet +, but very upright habit and ease of pruning make it manageable. Will grow in total shade to full sun. Drought tolerant. Very easy to keep in a pot for years.

* Punica granatum

Pomegranates

All pomegranates tolerate heat, wind, drought, poor soil. Great choice for west exposure. Fruiting forms yield large crops here with no effort on your part. Fruitless forms with showy flowers are available and are equally tough.

* Vitex agnus-castus

Chaste tree

Light blue flowers; white form also available. Fast-growing large shrub or small tree with light green palmate leaves. Tolerates heat, drought; will grow in partial shade.

Previous (October 2011) article: Easy Steps to Reduced Water Use

Here are some lists of drought-tolerant plants

Buddleia davidii and hybrids

Butterfly bush


Buddleia hybrids have become very popular for their long season of bloom and attraction to hummingbirds as well as butterflies. Most have a somewhat open habit and benefit from light pruning for greater density. Shown here is the variety Royal Red.

Callistemon citrinus

Lemon bottlebrush


This is the most commonly grown species of Callistemon. The common name comes from the lemon scent when you bruise the foliage. The bright red flowers appear every two to three months throughout the year, often including the winter months, and attract hummingbirds and bees. Watering too often leads to iron anemia; this plant prefers very infrequent irrigation

Eleagnus ebbingei 'Gilt Edge' has creamy-margined leaves on an upright shrub to 8 to 10 feet or taller. Edible fruit is popular with birds.

Feijoa sellowiana, Pineapple guava, has leaves that are green above, grey below. Flowers and fruit are edible.

Grevilleas are Australian shrubs with needle-like foliage and interesting, showy flowers over a long season. Hummingbirds are very attracted to Grevilleas. Shown here is the variety Scarlet Sprite.

Heteromeles arbutifolia, our native Toyon, is aptly called Christmas berry for the red fruit in wintertime. A yellow variant, Putah Gold, can be seen in the UCD Arboretum. Toyons grow at a moderate rate to ten feet or more. The flowers attract beneficial insects, and the berries attract songbirds.

Laurus nobilis, Grecian bay laurel, has shiny leaves that are so iconic that similar leaves on other plants are called 'laurel-leaf'. Crush the leaves to get the familiar pungent bay scent; this is the culinary bay.

Lavatera bicolor, Bush mallow, is a hibiscus relative that is cold-hardy and drought-tolerant. Showy pink-lavender blooms over a very long season.

Rhamnus alaternus 'Variegata', the variegated Italian buckthorn, has an upright growth habit. Songbirds like the tiny fruit.

Xylosma congestum

Shiny xylosma is one of the toughest, most useful evergreen shrubs around. Extremely tolerant of heat and drought, ok with some shade, it can be clipped as a hedge or even trained as a small tree. Variety Compacta is denser, has thorns.

Easy Steps to Water Conservation

Easy Water Conservation.

Water rates are in the news, and we are getting more interest in lower-water landscaping. It is estimated that 80% of residential water use is outside, with a very large percentage of that due to the lawn.
There are a number of easy ways to reduce your landscape water use.

First is to water correctly.

Water deeply, and as infrequently as possible for the types of plants you have chosen. For example, nothing needs water more often than twice a week during the summer here. Established shrubs and trees can often be watered once a week or less, if they get a thorough watering each time.
Most people could easily reduce their water use by 20% or more just by watering more deeply but less often.

Second is to zone your plants by water need.

You may wish to have a tropical oasis or fern grotto, so put those plants together in one area. You might want a lawn area. Your shrubs and trees don't need to be watered as often as those other types of plants.

Third is to reduce lawn area if possible.

Your lawn, properly watered, uses about 1000 gallons per 1000 square feet each week. And many people apply much more water than needed. Some turf species are more tolerant of infrequent watering, but in nearly any case the lawn is the highest water user in the landscape.

"Form follows function," Louis Sullivan said. Let your landscape form follow the actual use patterns of your family. Lawns are for kids and dogs, and are usually unneeded in front. Put lawn where you will use it, not just where you'll look at it.

Fourth is to choose plants that use less water.

For this article I'll focus on ground covering plants that can replace your lawn and use less water. First is the botanical name, then the common name if there is one. Landscape designers can choose from among Mediterranean plants, natives of South Africa and Australia, California natives, and more.

Herbaceous (soft) ground covers

* Aptenia cordifolia

Red apples

Popular succulent with red flowers. Rampant! Blooms freely, smothers weeds. Bees love it. Frost turns leaves to mush, but it quickly resprouts in spring.


* Dymondia margaretae

Very tough, low-growing ground cover for dry areas. Little yellow flowers. Some die-out if overwatered. May be damaged in cold winters, but recovers. Excellent between step stones.


* Epilobium species (formerly Zauschneria)

California fuchsia

Several species and varieties, ranging from 6" to 2'+. Bright orange-red flowers in late summer through fall attract hummingbirds. Tolerate drought or infrequent watering. Will grow in very light shade or full sun. Cut back when they look rough in the winter.


* Festuca ovina glauca

Blue or Grey fescue

Little tufts of silver grass foliage to about a foot tall. Single plants make a clump. Planted on 6 to 12 inch centers, makes an informal grey meadow.


* Gazania hybrids

G. leucoleana forms spread, have silver foliage, yellow or orange flowers. Clumping types have showier flowers, but don't cover ground as thoroughly--better in perennial borders.


* Lantana sellowiana

Trailing Lantana

Lavender flowers all summer and fall; there is a less-common white form. Grows to a foot tall, with each plant spreading 6 - 10'. Very tolerant of heat and drought.

Cut back in spring to remove frost damage. Also sold as L. montevidensis.


* Rosmarinus officinalis

Rosemary

There are selected forms with spreading habit, and others that are upright. They vary in height (1 - 2 foot +), depth of blue flower color. All can be used in cooking.


* Sedum confusum

Golden sedum

Dense, slow-growing succulent with shiny yellow-green leaves and showy yellow flowers. Great for edging; mix with grasses, use in pots, around stepstones. Takes sun or moderate shade, drought or average watering.


* Sedum spurium

Dragon's Blood sedum

Very low succulent grown for attractive reddish-bronze leaves. Tolerates sun or some shade; average watering or drought. Color intensifies in winter. 'Tricolor' has leaves that are white, pink, and green.


* Zoysia tenuifolia

Korean grass

Very dense, interestingly lumpy grass ground cover with needle-fine leaves. Dormant (brown) in winter. Very tough.

Vines that are planted as ground covers.

These are especially drought tolerant.


* Sollya heterophylla (fusiformis)

Australian bluebell creeper

Small, with dense, tiny, shiny leaves. Can be used as a ground cover. Grows slowly to about 6' tall when supported; 1 - 2' as a ground cover. Nodding blue flowers in summer; 'Alba' has white flowers. 'Boddy's Choice' is a very slow-growing type grown as a shrub or ground cover. Quite shade or sun tolerant, will grow under Eucalyptus trees.


* Trachelospermum asiaticum

Asian jasmine

Nearly always grown as a ground cover. Hardly ever flowers; grown for shiny leaves and exceptional durability. Can be tied up as a vine, but doesn't twine.


* Trachelospermum jasminoides

Star jasmine

Super fragrant flowers in May and June. Tolerates heat, cold, sun, shade, poor soil, drought or watering.

Shrubby ground covers

There are many woody plants that spread across the ground, making a shrubby ground cover. These tend to be two to three feet high.


* Artemisia 'Powis Castle'

Vigorous spreader with silver, ferny foliage. Extremely tolerant of heat, drought; ok in partial shade. Leaves have a strong medicinal scent. Completely shades out weeds. Can cover quite an area!


* Ceanothus species

Wild lilac

Several low spreading varieties are used as ground covers. Attractive shiny leaves; pretty blue flowers in spring. Ground cover forms range from a few inches to a few feet tall, spreading several feet. Don't plant where they'll have to be pruned. Water deeply and very infrequently in summer. California native.


* Euonymus fortunei 'Emerald Gaiety'

Variegated Wintercreeper

Low grower creeps along the ground, or can be clipped as a shrub. Very tough, tolerant of shade or sun. Flowers aren't noticeable. White portions turn pretty pink color in winter.


* Mahonia repens

Creeping mahonia

Shiny leaves, yellow flowers, shade tolerant. Slow to get going, but persistent and tough.


* Ribes viburnifolium

Catalina perfume, Evergreen currant

Will grow in considerable shade. Spreads steadily to make an attractive ground cover. Fragrant foliage. Very small light pink flowers in winter attract hummingbirds; red berries attract songbirds. California native.

How to do it.

You will need to kill out your grass somehow first. You can spray with an herbicide, or cover the area with black plastic for several weeks. Get your turf species identified since some grasses can be persistent and troublesome, especially bermudagrass. The plants listed don't need any special soil preparation. Rototilling will make planting easier. But you can just dig individual holes for the small plants.

Watering of the new plantings can be done with your lawn sprinklers, but you will water far less often. Or you can convert your system to drip irrigation. You may want to ask a landscape contractor for help if you do that.

Unplanted areas can be covered with a thick mulch to retain moisture and prevent weeds. Any bark or compost product can be used. Local rock yards can deliver bulk quantities at a reasonable price.
You need to do a little math to order the right amount of mulch. For two inches of mulch on 100 square feet, you need 16.7 cubic feet (100 divided by 6 = 16.67 cubic feet). There are 27 cubic feet in a cubic yard.

Green is good, but green lawns are high water users. So reducing your water consumption often begins right in the front yard, by choosing water-thrifty plants.

Some choices:

Aptenia cordifolia, commonly called Red Apples, is a fast-spreading succulent ground cover that smothers weeds. The red summer-long blossoms attract bees. It is best planted in spring or summer, as winter cold often causes top damage. But it recovers even from severe freezes.

Artemisia Powis Castle is a hybrid sagebrush. Tolerant of sun, drought, reflected heat, poor soil. It is a spreading shrub that suppresses weed growth. A single plant can spread six to eight feet or more.

Ceanothus is our native wild or mountain lilac. Forms of the shrub range from trees to a number of cultivars with low, spreading growth habit. The latter can be used as ground covers in very dry landscape plantings. Caution: Ceanothus need good drainage and cannot tolerate regular landscape irrigation.

A very tight-growing ground cover in the daisy family, Dymondia margaretae hugs the ground with silvery foliage. The small flowers are yellow. It can take light traffic and is suitable around step stones

Formerly Zauschneria, now Epilobium, commonly called California fuchsia. The late summer and fall flowers are orange-red and highly attractive to hummingbirds. Spreads steadily, though not invasively. Once established it needs little or no summer water.

There are many ornamental grasses that can tolerate, or even prefer, much less frequent irrigation that turfgrass species. Most grow in clumps, so they aren't lawn substitutes. But they can make attractive informal groundcovers. Shown here is Festuca ovina glauca, the blue or grey fescue. Planted close together, the plants look like an informal tall lawn or meadow.

There are trailing and clumping types of gazanias. The clumpers have very showy flowers over a long period, but don't spread enough to considered ground covers. Shown here in a hot, barely irrigated bed, these plants are several years old and blossom from October through May. The low spreading types have silver foliage and hug the ground.

Succulent ground covers can tolerate long periods without water, and Sedums (commonly called stonecrops) are very cold tolerant as well. Sedum confusum, the Golden sedum, can tolerate shade as well as full sun. Golden yellow flowers in spring.

Another sedum is the Dragon's Blood, named for the winter color of the foliage. Shown here is a variegated version: Sedum spurium 'Tricolor'.