Mother Nature's Backyard - A Water-wise Garden

Thursday, February 28, 2019

Plant of the Month (February) : Western Chokecherry – Prunus viginiana

Western Chokecherry (Prunus virginiana var. demissa):
Mother Nature's Garden of Health

It’s difficult to conjure up a February-appropriate plant that we haven’t previously profiled. But one that’s getting to a reasonable size is the Western chokecherry, Prunus virginiana var. demissa, in Mother Nature’s Garden of Health. The scientific name is pronounced: PROO-nus ver-jin-ee-AN-uh dee-MISS-uh.

Prunus virginiana is native to North America. It once grew wild in much of Canada, the United States and northern Mexico. There are two recognized varieties: Prunus virginiana var. virginiana (the eastern chokecherry, native to the eastern US and Canada); and Prunus virginiana var. demissa (the western chokecherry, native from WA, OR and CA east to the Rockies and Mid-West).

In California, Western chokecherry grows in many wooded and shrubby habitats from San Diego County to the Oregon border, at elevations below about 8000-10,000 ft. (2500 m.). It’s not native to either the Southern California coast or the Central Valley, and grows mostly in areas with winter snow, or near seeps and stream bottoms. In Los Angeles County, it can still be seen in the Liebre and San Gabriel Mountains – and in gardens. It grows in most foothill and mountain plant communities, especially scrub lands, oak/pine woodlands and coniferous forests.

Western Chokecherry (Prunus virginiana var. demissa):
Four year old plant

Prunus virginiana is a large shrub or small tree. It varies greatly in size and form, sometimes appearing as a 3-4 ft. shrub. In other sites, it can achieve mature heights of 20-30 ft. (6-9 meters). Its mature spread can be 15-20 ft. The overall form is erect, with many slender branches. The bark is reddish on new growth, becoming gray. Some plants are shrub-like, with much branching from the base. Others are more tree-like, with a central leader. In some situations, Chokecherries form dense thickets. This characteristic makes them particularly suitable for hedgerows and screens. For more photos of Chokecherry plants see reference 1, below.

Western Chokecherry (Prunus virginiana var. demissa): leaves

Chokecherries are winter-deciduous, losing all their leaves in late fall in colder climates. In cold climates, leaves turn an attractive gold or orange in fall, making them a good source of fall color. In warmer sites (like Mother Nature’s Garden of Health), plants may retain their leaves well into winter in some years. The leaves are simple, ovate to elliptical, with finely-toothed margins. The new leaves are bright green in spring, maturing to medium or dark green above and slightly paler green beneath. The leaves contrast pleasantly with the bark, which is smooth and dark red on younger twigs and often gray on mature branches. The foliage is a larval food source for Small-eyed Sphinx Moth & Columbia Silk Moth.

Like many members of the genus Prunus, parts of the plant are toxic. New growth, wilted leaves, or plant parts injured by frost or drought are particularly harmful if ingested by humans or animals. Domestic cattle and sheep have been poisoned eating too much foliage. Despite this, Chokecherries are widely used as a forage plant in wild. Animals as varied as bears, moose, coyotes, bighorn sheep, pronghorn, elk, deer and smaller mammals all browse Chokecherry.

Western Chokecherry (Prunus virginiana var. demissa): Flowers
photo by Mary Winter, Cal Photos

Chokecherry flowers have many characteristics typical of the genus Prunus. The flowers themselves are small, white to cream-colored, with five simple petals (flower parts in fives). The flowers are arranged along drooping, 2-5 inch flowering stalks, and may be densely packed. Plants are very showy in bloom, and the species is often used as an ornamental shrub/tree in home landscapes. The flowers are sweetly scented – with a slight hint of almond – and attract a wide range of pollinators, including native bees and butterflies.

Western Chokecherry (Prunus virginiana var. demissa): ripe fruits

Chokecherry is probably best known for its fruits. The fruits are small (1/4 to ½ inch), shiny ‘cherries’ that begin green, then ripen to either red, dark-red or almost black (Four Corners States; Rockies). Even when ripe, the raw fruits are very bitter, hence the common name ‘Chokecherry’. None-the-less, birds and animals relish the fruits. If you grow Chokecherry for its fruit, you may need to protect the ripe fruits from hungry birds!

The seeds (pits) contain high concentrations of hydrogen cyanide, a potent poison. Fruits should not be eaten raw; however they can be cooked to render the fruit non-toxic, particularly when the seeds (pits) are removed after cooking. Chokecherry jelly and syrup are highly prized for their color and cherry flavor. They are one of the favorites at garden gourmet events in our gardens.

Western Chokecherry (Prunus virginiana var. demissa): jelly

Chokecherries can be grown in all but the heaviest clay soils. They don’t do well in soils with pH > about 7.8. They are shade tolerant and do well in part-shade and under trees. While they can be grown in full sun (with adequate water), they are probably most successful when given afternoon shade in Southern California. Chokecherries like a richer soil than many of our local natives. Organic mulch can be used to supply nutrients – or fertilize with a low-dose fertilizer in spring.

Chokecherries also need some summer water. They have some deep roots, but also many shallow roots. In the lowlands of Southern California, they likely will need water every 2-3 weeks from June through September. We water our Prunus virginiana every other week in Mother Nature’s Garden of Health. The soil dries out between waterings in our clay-loam soil. We’ve also located our plant on the north side of a tall wall, providing more shade than in most of our garden.

Western Chokecherry (Prunus virginiana var. demissa)

Like most Prunus (plums, cherries, peaches, nectarines, apricots, almonds) Prunus virginiana is susceptible to black knot fungus, fireblight, and several other diseases. In general – and with judicious watering – it is healthier then the domesticated Prunus. But keep an eye out for disease, and prune out diseased wood right away (using sterile pruners). Western chokecherry has a pleasant natural shape. Unless you’re training your Chokecherry to a tree or espalier it won’t need much pruning. But you will need to prune off the root suckers, which can be common in this species.

If you’re in the market for a large shrub/small tree Prunus virginiana has much to recommend it. It can be used in a mixed hedgerow or pruned up as a shade tree. In our garden, we are espaliering our Chokecherry along a wall (most Prunus are good candidates for espalier). The foliage is pleasant and the flowers are showy and fragrant. The fruits can be used to make delectable jelly, syrup, fruit leathers, cordials and wine – or left as habitat for fruit-eating birds.

Western Chokecherry (Prunus virginiana var. demissa):
Rancho Santa Ana Botanic Garden, Claremont, CA

Traditional medicine used tea made from the bark for stomach ailments, coughs, colds and diarrhea, and as a sedative. The ‘tea’, as well as a poultice made from the leaves, was used to treat cuts, sores, bruises. Dried, powdered bark was used similarly. The ripe fruit is a laxative. And leaves, bark and fruits can be used as natural dyes.

In short, Western Chokecherry is an attractive shrub/tree with many uses. It’s one of those native plants that provides lots of value for its cost – and the space it takes in a garden. If you need a large shrub or small tree, Prunus virginiana may be right for your garden.

Western Chokecherry (Prunus virginiana var. demissa):
in garden, Montrose CO

https://calphotos.berkeley.edu/cgi/img_query?where-genre=Plant&where-taxon=Prunus+virginiana+var.+demissa

For a gardening information sheet see: http://www.slideshare.net/cvadheim/prunus-virginiana

For plant information sheets on other native plants see: http://nativeplantscsudh.blogspot.com/p/gallery-of-native-plants_17.html

We welcome your comments (below). You can also send your questions to: mothernaturesbackyard10@gmail.com

Tuesday, February 12, 2019

Farewell to Connie Vadheim – Blog Master

Our longtime Blog Master, Dr. Connie Vadheim, is moving to Montrose, Colorado. Follow her on our new, sister blog: Mother Nature’s Montrose (Colorado) Garden at https://mothernaturesmontrosegarden.blogspot.com/

Saturday, December 29, 2018

Plant of the Month (December) : California Scrub Oak – Quercus berberidifolia

California scrub oak (Quercus berberidifolia): Mother Nature's Garden of Health,
Gardena, California

Limited gardening space requires thoughtful plant choices. Good plants for smaller gardens combine beauty, usefulness and habitat value; what we like to think of as ‘value added’ plants. Some of the best evergreen habitat plants are the native live oaks. They are also attractive and provide food (for those willing to process the acorns). And fortunately, several local live oaks are small enough to be considered for suburban gardens. One of our favorites is Quercus berberidifolia. The scientific name is pronounced: KWER-kus ber-ber-id-i-FO-lee-uh.

California is blessed with twenty-one species of native oaks. Of these, sixteen are native to Los Angeles County – a remarkable amount of oak biodiversity. The Southern California oaks are mostly evergreen (thirteen of sixteen species). And of the evergreens, only five (Quercus agrifolia; Q. chrysolepis; Q. engelmannii; Q. tomentella; Q. wislizeni) are large trees. The rest are large shrubs or small trees, of a size suitable for smaller landscapes.

California scrub oak (Quercus berberidifolia) vs. Nattall's scrub oak Quercus dumosa)

Among the smaller S. California live oaks, Quercus berberidifolia and Quercus dumosa (Nuttall’s scrub oak) are most widely available in the nursery trade. Like most oaks, the scrub oaks of California are prone to hybridization, producing a number of hybrid forms. It’s likely that some plants available for purchase are actually hybrids. And there’s still considerable debate about the range and characteristic morphology of these two species. The interested reader is directed to references 1-6, below, for more on this evolving topic.

Quercus berberidifolia is known by several common names: Inland Scrub Oak; California scrub oak; Scrub oak. It belongs to the Family Fagaceae (the Beech Family) and is a member of the White Oak section of the genus Quercus. Its range extends from the Northern California coastal foothills to Baja California, Mexico. In Los Angeles County, it can be found in the Santa Monica and Verdugo Mountains and the foothills of the San Gabriel Range, below about 5000 ft. elevation. It is most commonly associated with the chaparral plant community.

California scrub oak (Quercus berberidifolia):
3 years in ground

California scrub oak (Quercus berberidifolia):
4 years in ground

The California scrub oak is a small, evergreen or semi-evergreen shrubby oak. When young, it has a somewhat scraggly appearance (above). With age, it develops its characteristic mounded form. It typically grows no taller than about 9-10 ft. (to 3 meters), but may grow 15+ ft. in prime locations. It often is slightly wider than tall: usually 15-20+ ft. wide. It has light green-gray to gray, smooth bark. The foliage is dense, making this a good screening shrub. The reader is directed to references 7-9, below, for more photos.

Quercus berberidifolia is a slow growing plant, adding 1-2 ft. of new growth each year. It’s also long-lived in the wilds – likely several hundred years. It’s often difficult to tell the precise age of oaks that grow in fire-prone areas. Like many local oaks, Quercus berberidifolia re-sprouts after a fire. So the age of individual stems may be significantly less than the actual age of the plant. For more on the fire-relations of this species, see reference 10.

California scrub oak (Quercus berberidifolia): foliage

Quercus berberidifolia has small, often holly-like leaves – hence the scientific name. The leaves are thick, stiff and shiny to dull above. The undersides of the leaves have sparse hairs (trichomes). The shape of leaves can vary tremendously, even on a single plant (see references 9 and 11 for examples).

Like all oaks, Quercus berberidifolia is wind pollinated. The separate male and female flowers occur on the same tree. Plants bloom in winter or early spring – usually February or March at lower elevations. The male flowers, with their yellow pollen, grow on dangling, one-inch catkins. The pollen is not usually a problem for human allergy sufferers. The female flowers are often hidden by leaves. The acorns, which develop from the female flowers, are broad and chunky. They look distinctively different from the longer, tapered acorns of the Coast live oak (Quercus agrifolia) and Quercus dumosa. Acorns ripen 6-8 months after pollination. New seedlings can be started quite easily from fresh acorns in the fall.

California scrub oak (Quercus berberidifolia): sunny site

California scrub oak likes a site with full sun to part-shade. It grows in most well-drained local soils except those with high salinity (no recycled water). It can succeed in clays and clay-loams, as long as summer water is kept to a minimum. In soils with reasonable drainage, it can be deeply watered every 4-6 weeks during the dry season. The first 4-5 years, when plants are establishing, they require monthly water in most locales. Then plants are quite drought tolerant. This species has deep roots that require a few years to develop.

It’s best to let oak trees self-mulch, and Quercus berberidifolia is no exception. Oak leaves help with soil moisture retention. They also contain plant chemicals that likely provide protection from pests and diseases. The leaves also repel slugs, snails and grubs. So, leave the leaves in place when they fall.

California scrub oak is generally easy to grow. It is susceptible to several oak pests, including several types of borers, and to soil and other fungal diseases. For an excellent guide to the pests and diseases of California oaks see reference 12.

Scrub jays and others love acorns!

The California scrub oak is an excellent habitat plant. The dense foliage provides cover and nesting sites for birds. The shade and cover are utilized by smaller, ground dwelling animals from rabbits to lizards and doves. The acorns are a favorite food of Jays, woodpeckers, squirrels and other animals. In the wilds, young foliage is sometimes browsed by larger animals (deer, sheep, bears).

Oaks in general provide important habitat for a wide range of beneficial insects. These, in turn, attract the insect-eating birds. Butterflies for which this oak provides larval food include the California Sister, Propertius Duskywing, Mournful Duskywing, Golden Hairstreak, and Gold-Hunter's Hairstreak.

California scrub oak (Quercus berberidifolia): habitat
for Duskywing butterflies

The acorns of Quercus berberidifolia are edible, though not as tasty as those of other native oaks, particularly the Black oaks. Acorns must be leached of their bitter tannins – an involved process – before being useful as acorn meal. The galls that grow on oak trees are strongly astringent and were traditionally used in the treatment of bleeding and chronic diarrhea.

California scrub oak (Quercus berberidifolia)

In summary, native scrub oaks can be useful evergreen shrubs or small trees in suburban landscapes. They can be used as background shrubs, for large hedges/hedgerows or pruned up as small shade trees. They grow well on slopes, with a minimum of care once established. They can be planted in dry parking strips and can even be used as bonsai or container plants. They can be shaped or left to develop their own natural form. They are resilient and water-wise.

Oaks also have much to recommend them as representatives of our California heritage. They bring many types of wildlife to the garden and even provide a source of human food. They recall a time when oaks were key to human survival. They are among our most important native plants and their habitat is disappearing in some areas. That’s why Los Angeles County oaks are protected by The Los Angeles County Oak Tree Ordinance. And these are just a few reasons to plant Quercus berberidifolia in your own garden.

California scrub oak (Quercus berberidifolia): part of mixed hedgerow,
Mother Nature's Garden of Health

For a gardening information sheet see: https://www.slideshare.net/cvadheim/gardening-sheet-quercus-berberidifolia-126900433

For plant information sheets on other native plants see: http://nativeplantscsudh.blogspot.com/p/gallery-of-native-plants_17.html

____________________

We welcome your comments (below). You can also send your questions to: mothernaturesbackyard10@gmail.com

Friday, October 5, 2018

Plant of the Month (October) : Laurel Sumac – Malosma laurina

Laurel sumac (Malosma laurina): Mother Nature's Pollinator Garden

Southern California is home to an array of remarkable native shrubs. Many are more drought-tolerant than the non-natives commonly used in local landscapes. In addition, the natives have interesting and useful attributes that make them welcome additions to the garden. One such shrub – if one has the space – is our plant of the month, Laurel sumac. The scientific name is pronounced mal-OZ-muh low-RINE-uh.

Laurel sumac is a member of the Anacardiaceae (Cashew) Family, which includes such well-known S. California species as Fragrant sumac (Rhus aromatica [Rhus trilobata]), Lemonadeberry (Rhus integrifolia), Sugarbush (Rhus ovata), and Poison oak (Toxicodendron diversilobum). The family also includes Pistachios, Cashews and the non-native Pepper Trees often used in S. California landscapes. For more on this interesting family see: http://mother-natures-backyard.blogspot.com/2014/12/plant-of-month-december-lemonadeberry.html.

Malosma laurina grows from Fresno and San Luis Obispo Counties south to Baja California, Mexico. In Los Angeles County, it can still be seen growing wild on Santa Catalina and San Clemente Islands, in the Santa Monica Mountains, San Gabriel foothills, Verdugo Mountains, on the Palos Verdes peninsula and in other undisturbed places. Laurel sumac’s distribution is limited primarily by its frost-sensitivity. In past times, orchardists used this plant as an indicator of frost-free zones – places to plant crops such as citrus and avocados. [1]

Laurel sumac (Malosma laurina): Palos Verdes Peninsula

Laurel sumac usually grows on dry ridges and canyons below 3000' in chaparral and coastal sage scrub. It’s occasionally found in S. Oak Woodlands, but only where frosts are rare. Common associates are Black, White and Purple sages, California sagebrush, Toyon, Lemonadeberry, Sugarbush, Bigberry manzanita, California encelia and the Goldenbushes (among many others).

Laurel sumac was first collected in San Diego County in the 1870’s by Daniel Cleveland and Edward Palmer. It was more widely collected in the 1880’s and 1890’s by such notable California plantspersons as the Parish brothers, the Brandegees, Blanche Trask and J.H. Barber. The species was first introduced into cultivation by Theodore Payne. [2] For more on these early collectors see: http://mother-natures-backyard.blogspot.com/2018/05/californias-fascinating-native-plants.html

Laurel sumac (Malosma laurina): growth habit

Laurel sumac is a large shrub or multi-trunked small tree. At maturity, it reaches heights of 10-15 ft. (3 to 4.5 meters) and diameters of about the same. In favorable locations, a plant can be as much as 20 ft. tall and wide. The overall shape is rounded to slightly sprawling. In the wilds, Laurel sumac can create thickets in favorable sites. This is likely due to seeds falling near parent plants.

Laurel sumac (Malosma laurina): branches

The trunks and branches are substantial, and like Toyon and Lemonadeberry, the wood is moist and rather fibrous. The bark on young stems is red-brown; it becomes an attractive pale gray-brown on older branches. The shape and bark color make this a good alternative to Oleander, Photinia, Pittosporum and Xylosma.

Laurel sumac (Malosma laurina): young leaves

One of the best reasons to plant Malosma laurina is its year-round interest and color. Laurel sumac is evergreen, a characteristic prized in and of itself. But ‘evergreen’ scarcely does justice to the variations in leaf color typical of this species. Young leaves and branch tips are a brilliant red/orange (above), due to anthocyanin pigments that protect from herbivory and sun-scald. This red color is often retained on the edges of mature leaves. New leaves are produced year-round, even in summer/fall.

Laurel sumac (Malosma laurina): mature leaves

Mature leaves are somewhat leathery, medium to dark green and folded along the midrib like a taco shell (see above). The leaves are medium to large – four to six inches in length. The leaf shape is simple and reminiscent of the leaves of the Laurel – hence both the common and scientific names. Senescent leaves turn yellow (below) adding to the colorful foliage in this species.

Laurel sumac (Malosma laurina): senescent leaves

All parts of Laurel sumac are pleasantly scented. The flowers and sap are aromatic, and the leaves release scented, volatile chemicals into the air. On a warm or wet day, the characteristic aroma can be smelled at a distance. Even fallen leaves release the aroma when walked upon. For more on gardening with scent see: http://mother-natures-backyard.blogspot.com/2018/03/gardening-for-health-2-magic-of-scent.html

The scent is a unique blend: bitter and somewhat fruity. It’s been described as the scent of bitter almonds, unripe apples or citrus. It’s an aroma unique to the plant, and for many, it’s the ‘scent of the California chaparral’. As a note of caution, some people have nasal allergies to the plant chemicals and/or pollen. In addition, the sap can cause contact dermatitis (short-term skin allergy) in sensitive individuals. Gloves should be worn when pruning or handing the plant.

Laurel sumac (Malosma laurina): flower buds

Laurel sumac (Malosma laurina): flowering plant

Malosma laurina blooms most often in late spring or early summer. In the Gardena Willows Wetland Preserve (where our gardens are located) it commonly blooms in June or July. This is quite a showy bloomer. The flower buds are a pleasant pink that contrasts nicely with the spring leaves. The flowers themselves are creamy white. The flowers grow in dense clusters at the ends of the branches (above). The look reminds one of a lilac bush with white flowers.

Laurel sumac (Malosma laurina): close-up of flowers

The flowers themselves are small, simple, with five rounded petals. The flowers can be either bisexual or unisexual (see photo above); in at least some cases, plants can be functionally either male or female. The details are currently being studied, so we’ll know more about the reproductive biology of Laurel sumac in the future. The interested reader is directed to ref. 3 (literature) for more on this fascinating topic.

Laurel sumac (Malosma laurina): ripening fruits

The flowers attract European Honey bees, native bees, pollinator flies and likely other pollinators. The fruits are small and not particularly showy. They start off green and are white when ripe. The dried fruits, which are dark brown, remain on the plant into fall and winter. The dried fruits add fall/winter interest (see below). The fruits and dried seeds are eaten by a number of seed-eating birds, but are particularly loved by song birds. In fact, this species provides good bird habitat: food, perches, shade and nesting sites.

Laurel sumac (Malosma laurina): dry fruits

Malosma laurina takes a year or two to establish, then it grows to size fairly quickly thereafter. In the wilds, plants can live at least 30-45 years. The actual age limit is difficult to determine. Plants burn to the ground in a fire. But an underground sprouting root (lignotuber) remains alive, allowing plants to re-sprout quickly (often the first green seen after a fire). So, the age of a mature plant may be older than the age of a single trunk.

Laurel sumac needs full sun and prefers well-drained soils, with a pH 6.0-8.0. It does well on slopes (as it does in the wilds). It is intolerant of low temperatures and pH much above 8.0. The plants are relatively insect-resistant and do best when leaf litter is allowed to accumulate (this is true of many chaparral shrub species). The plant can be pruned up as a small tree, and yearly fall trimming will keep it from getting rangy. Old shrubs can even be cut back hard (even coppiced) to rejuvenate them.

Once established, Laurel sumac is quite drought resistant. Plants have roots that grow deep – 40 feet or more in some cases. Mature plants get by on occasional to no summer water (no more than one deep watering a month). But they do need adequate winter/spring water, so supplement as needed.

Laurel sumac (Malosma laurina): mature plant,
Heritage Creek Preserve, CSU Dominguez Hills, Carson CA

Future climate change may prove challenging to this species. Several of us have noted branch die-back in established plants (see above). Early research suggests that this is due to fungal disease, and some individuals seem to be more susceptible than others. As with many local plant disease/pest problems, drought stress appears to be a contributing factor to susceptibility. For more on this topic see ref. 4, below.

Laurel sumac (Malosma laurina): at home on the
Palos Verdes Penninsula

Malosma laurina is a great choice for slopes and for wildland interface areas. If planted in areas prone to wildfires, it should be planted away from structures, and the lower 1/3 of small branches removed. Laurel sumac makes a great background plant, with its evergreen leaves and flowers. It looks particularly good when paired with its natural associates: the plants of the S. California coastal sage scrub.

Like Toyon, Laurel sumac is quite versatile. It can be pruned up as a small, multi-trunk tree or used as a hedge, screen or hedgerow. As a hedge, it can be pruned formally or informally. If space is limited, Laurel sumac can even be espaliered along a wall or free-standing support frame. We’re in the process of training the plant in our Bie Havn Pollinator Garden as an espalier against the back wall.

Laurel sumac (Malosma laurina): espalier in Mother Nature's
Bie Havn Pollinator Garden

In terms of practical uses, the dried fruits can be ground into flour. The young branches can be split and used in making twined baskets. The plant is a minor medicinal plant among the Chumash and Kumeyaay, who use a root bark tea for dysentery and baths for women’s ceremonies.

In summary, Malosma laurina is a key species of our local coastal sage scrub and chaparral plant communities. It’s an evergreen shrub with the versatility to function as a tree, hedge or espalier. It looks right at home with many of the plants used in S. Calilfornia native plant gardens. And it adds to the ‘fragrance of the wild’ that makes our S. California gardens so captivating. If you want to bring a bit of native California into your garden, this is a good shrub to consider.