Tree of the Week: Cape Chestnut

The Cape Chestnut -- Calodendrum capense

In bloom the pink-draped Cape Chestnut is a magnificent sight. Linnaeus’ pupil Carl Peter Thunberg gave it the "beautiful tree from the Cape" Greek and Latin scientific name. English explorer William Burchell (1782-1863), who in 1819 recommended South Africa for emigration purposes, thought that this South and tropical African tree resembled the chestnut tree he was used to in the U.K., hence the common name, but there is no relationship. The tree is a member of the citrus family.

The Cape Chestnut grows moderately slowly to become a handsome, dense, round-headed 25- to 40-feet briefly deciduous to almost evergreen tree. The trunk is smooth and mottled gray. Medium green oval leaves, up to 6 inches long, share this citrus family characteristic: They carry oil glands that are visible as tiny translucent dots when the leaf is held up to the light, and emit a strong smell when crushed. Candelabra-like, foot-long upright flower clusters consist of five narrow strap-like lilac-pink petals each, alternating with five stamens; the tree has to be at least 5 years old to put on a good flower show. Flowers are followed by brown woody capsules that split open to reveal five smooth, black seeds. The Cape Chestnut wants full sun and a location protected from strong winds; it dislikes sandy soils and cold. The tree will take some drought, but performs and blooms far better with regular water.

Yangu oil pressed from the seeds is used in skin care. The wood is fairly hard, bends well and is easily worked.   

--Pieter Severynen

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Photo: Pieter Severynen

Tree of the Week: The northern catalpa

The northern catalpa -- Catalpa speciosa

Spectacular in bloom with big, upright clusters of white flowers set off against big, bold leaves, the catalpa shouts for attention in spring. At other times, the impression is more of a country dweller lost in the city: Such as when the long-lasting Indian beans -- up to 20-inch-long, bean-like seed capsules -- dangle from the branches or when the sloppy twigs’ arbitrary direction of growth all over becomes exposed during the leafless seasons. Some find the tree messy and weedy looking, especially in winter.

Originally from Mississippi River valleys, an area stretching from Indiana to Northern Arkansas, this tough tree with the Indian name was widely planted for quick shade, durable fence posts and fine-grained wood. Occasionally it was used for avenue planting in Ohio. The tree is also known as western catalpa and is a member of the Bignonia family.

Fast growing when young, the deciduous northern catalpa eventually reaches 40 to 60 feet tall and 20 to 40 feet wide. It tolerates climate extremes. The crown will be irregularly shaped and the trunk and branches crooked, unless pruned. Wood is brittle. Shallow fissures and scaly ridges define the gray to reddish-brown bark, while round or elliptical leaf scars decorate the twigs. The soft, bright green, 6- to-12-inch-long heart-shaped leaves are fuzzy underneath and so tender and large that the wind may tear them apart; it is best to plant the catalpa in a protected spot.

White, bell-shaped flowers, 1 inch long, with yellow and purple spots on the insides, are arranged in footlong clusters. Long, thin, brown beans will follow and may stay on the tree for months. The catalpa is not particular as to soil and water. It is invasive in some areas of high moisture.

The closely related common or southern catalpa, C. bignonioides, is a bit smaller and the leaves release an odd odor when crushed. A hybrid with a Chinese species has blackish purple leaves. The otherwise similar-looking Empress tree, Pauwlonia tomentosa, with which the northern catalpa is sometimes confused, has lavender flowers.

-- Pieter Severynen

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Photo: Pieter Severynen

Tree of the Week: Purple Robe Locust

The Purple Robe Locust –

Robinia x ambigua

Plant breeders keep hoping for a big success. The tough Black Locust, Robinia pseudoacacia, has been crossed several times with the shrub-like Clammy Locust, Robinia viscosa. The tall and graceful Black Locust, an eastern U.S. native, tolerates climate extremes and neglect; has annoying thorns and surface roots; is often planted around farmlands; and has become naturalized in some California locales. The Pink Locust, also an Easterner, is better behaved and smaller, with more desirable flowers. The hope was that the resulting ambigua hybrid species would combine the best characteristics of each parent, and yield mild-mannered cultivars with beautiful flowers. Opinions vary as to the qualities of the Descainea, Idaho and Purple Robe Locusts offspring. Sometimes even the Purple Robe parentage is suspect: Some people consider it only one of many cultivars (selections) of the Black Locust itself or a hybrid of other species.

The deciduous Purple Robe Locust grows moderately fast to a fairly open, attractive, rounded 40-foot-tall by 30-foot-wide tree. Brown, rope-like ridges with intervening furrows define the bark. Branches and bark may carry thorns. Wood is rot resistant, but branches are brittle; structural pruning in youth helps. Nitrogen-fixing bacteria inhabit the aggressive roots; the trunk has a broad, fluted base. Dark green, 10-inch-long compound leaves are pinnate feathered, with as many as 20 ovate leaflets. Showy, fragrant, deep pink to purple pendulous flowers resemble those of Wisteria and yield excellent honey. Flat, purple-brown seed pods, to 4 inches long, follow the flowers. The Purple Robe Locust likes full sun or dappled shade and will take most any soil, drought or lawn watering. The tree is susceptible to several pests and diseases, including borers and leaf miners. Still its faults are considered minor enough that several communities use it as a street tree.

Locust trees are named Robinia pseudoacacia after Jean and Vespasian Robin, French 16th and 17th century botanists. 

-- Pieter Severynen

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Photo: Pieter Severynen

Tree of the Week: Queensland Lacebark

The Queensland Lacebark, Pink Flame Tree -- Brachychiton discolor

This Australia native tree is an ornamental but variable individual, a member of a 30-odd related group of species of trees and shrubs in the genus Brachychiton.The trunk is often, but not always, bottle shaped (to accommodate water storage). Leaves may be deeply lobed or less so, and are quite variable insize. Parts of the younger tree, or the whole tree, may be blooming on dry season deciduous wood, so that some branches may be bare or in bloom, while other ones are not. Time of leaf drop is erratic. The genus name refers to the loose coat or short tunic, brachis chyton that covers the seed; sometimes the old genus name, Sterculia is still used.

The Queensland Lacebark is a briefly deciduous tree that grows at a moderate pace into a strong central leader shape until it finally reaches 40 to 60 feet tall. Pyramidal in youth, it starts spreading in middle age to become a good 30 feet wide. On older trees, the trunkusually assumes a distinct bottle shape; that and its solid shape make for an imposing appearance. Bark is mainly smooth and whitish gray. The 8-inch-long, 6-inch-wide leaves are blue-green atop and whitish underneath; they may be deeply lobed and resemble those of the California plane tree, Platanus racemosa,or have no, few or shallower lobes, especially when the tree becomes older.

Young trees bloom partially or wholly on bare branches on what was the tree’s dry season in its area of origin, or at least what the tree remembers that to be; older trees tend to drop all their leaves before blooming. Pink bell-shaped flowers appear in summer. Blossoms and the canoe-shaped fruit are covered with rusty brown fuzz on the outside. Leaf, flower and fruit drop may appear messy to some.  The Q.L. prefers full sun, little to moderate water and will take most any soil.

Relatives one is likely to see here include the Flame Tree, B. acerifolius, with spectacular red flowers; the Bottle Tree, B. populneus, appreciated in the desert for its shade; and the Queensland Bottle Tree, B. rupestris, with a characteristic bottle shaped trunk.

--Pieter Severynen

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Photo: Pieter Severynen

Tree of the Week: Japanese black pine

 

Japanese black pine -- Pinus thunbergii

The Japanese black pine is a godsend to people who love to shape trees. It will take kindly to most any attempt to make it into something it is not. Native to northeastern China, Korea and Japan, it is named after 18th century Swedish naturalist Carl Peter Thunberg, who spent some time in Japan; sometimes the species name is spelled thunbergiana. Its malleability and adaptability make it a popular landscape tree.

In the Pacific Northwest the tree can grow fast, to 100 feet tall by 40 feet wide. In Southern California it may be a slow to moderate grower, up to 25 by 25 feet. This evergreen charms with its open, irregular to pyramidal growth; spreading, horizontal branches; and often leaning trunk. Contrary to current practice it actually can get by with little or no pruning.

The bark is gray, becoming covered with thick plates when the tree gets older. Needles are dark green, 5 to 7 inches long and borne in groups of two. Stiff upright shoots, called candles, appear at the ends of the branches in spring. Male and female cones occur on the same tree. The female ones develop into little woody pine cones. The roots are not invasive, will take most types of soil, even if happiest in well-drained soil, and are drought tolerant. Unfortunately the tree is subject to attack by the native American pinewood nematode, Bursaphelenchus xylophilus, which, followed by blue stain fungus, may be lethal. 

The Japanese black pine is resistant to air pollution, high winds and salt spray. Dwarf cultivars are used as classic bonsai subjects. Many cultivars are grown, including some with yellow striped or edged leaves. 

--Pieter Severynen

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Photo credit: Pieter Severynen

Tree of the Week: Weeping Bottlebrush

The Weeping Bottlebrush -- Callistemon viminalis

In spring, long, bristle-like stamens cluster together in intensely red, 6-inch long, hanging, bottlebrush-shaped cylinders that look like they would make doing the dishes fun. The name of this New South Wales, Eastern Australia tree means "beautiful stamens." The tree is from the Myrtle family, and a tiny movement is underfoot to reclassify it as ‘Melaleuca’ rather than keep calling it ‘Callistemon’. The tree grows a little beyond the boundaries of Coastal Southern California and South Florida.

The weeping bottlebrush is a small, irregularly round-headed, open, fine-textured weeping evergreen tree that grows at a medium pace to 20 feet tall by 15 feet wide, but may reach 30 feet. Branches droop; twigs and trunks are gray and stringy. Pruning will give the tree structural strength but may diminish the weeping effect if done without insight. The narrow, light green leaves are 4 inches long, sometimes more. Flowers, or at least the stamens, are bundled in brilliant red clusters that put on a spectacular show; spring is the main blooming period. Fruits, consisting of tiny round woody capsules, are almost inconspicuous. The tree wants full sun and is drought-resistant but looks better with some water. It will take most soil conditions and even accept lawn watering; roots are well-behaved. The tree is not very demanding.

Selected cultivars offer larger flowers, denser foliage. ‘Little John’ is a 3-foot dwarf form. The lemon bottlebrush, C. citrinus, lacks the weeping aspects, but it is a little hardier than the weeping one. Its leaves smell lemony, and it too comes in several selected varieties.

-- Pieter Severynen

Photo: Pieter Severynen

Tree of the Week: The Loquat

The Loquat Tree -- Eriobotrya japonica

It’s hard not to like the loquat. The tree is small, easy to grow, doesn’t need much room, has big-veined tropical-looking leaves, fragrant flowers and attractive, small-plum-sized golden yellow fruit. Grown from seed it produces acceptable fruit, but for really tasty and large fruit it is wise to plant one of a wide selection of grafted varieties such as "Champagne" (in warm areas), "Gold Nugget" (in cooler parts) or MacBeth (for very large fruit).

Indigenous to southeastern China, the tree had a long cultural history there and in Japan before it reached Paris and London in the late 1780s. It was common in California by the 1870s. The tree is widely grown in warm countries. It is a member of the rose family.

The evergreen loquat grows to some 15 to 30 feet tall and wide. The gray trunk has a tendency to become multi-stemmed. New wood may be a little brittle; it helps to build up a strong framework when the tree is young.  New branches have a woolly feel. The tree is ornamental even without the fruit, but flowers and fruit are a nice bonus. Leaves are 6 to 12 inches long, starkly veined and netted; they are often used for decorations. Flowers are borne in fall or winter in clusters of fragrant, off-white flowers.

In the Southland the fruit ripens in spring. It always contains several large shiny brown seeds. Fruit is at its sweetest when just at the point that it begins to shrivel. It can be eaten fresh or used in pies or preserves. Food production is best in full sun, but the tree will take half shade, regular water to half-dry conditions and most any soil. Although the tree is easy to take care of, it can succumb to some diseases, including pear blight, Phytophthora and leaf spots caused by fungi.

The related bronze loquat, E. deflexa, is an ornamental tree with leaves less leathery and more copper in color than the edible loquat. It does not produce edible fruit.

--Pieter Severynen

Photo: Pieter Severynen

Tree of the Week: The dawn redwood

 The Dawn Redwood -- Metasequoia glytptostroboides

Japanese paleobotanist S. Miki described samples of Metasequoia in 1941 as a separate fossil genus, not belonging to the same genus as the California redwoods. Four years later, forest researcher Z. Wang found four unknown trees in a temple near China's Sichuan province. A year later, Beijing professors Hu and Cheng organized another expedition to find more of these new trees. It turned out that Miki’s 100-million-plus-year-old fossils had direct, living relatives. Much of the remaining tree population was logged after the revolution of 1949.

The original tree population is critically endangered in its native habitat of the damp ravines of west China’s Sichuan, Hubei and Hunan, but in the meantime the tree has spread all over the world (seeds made it to the Boston, Mass., Arnold Arboretum in 1948). The original trees came from too few seeds and suffered from genetic shortcomings; later seed collecting in China corrected this shortcoming.

The dawn redwood is one of the few deciduous conifers. The tree can grow quite fast (4 to 6 feet a year when young in California) and so far reaches a pyramidal 90 feet tall by 20 feet wide. The thin branches are arranged around a stout, reddish-gray and peeling central trunk with fissured bark. Older trees show wide buttresses on the lower trunk. In older trees the bole may become beautifully contorted if not stripped of its branches.

In leaf the tree resembles the bald cypress, Taxodium distichum, as well as the coast redwood, Sequoia sempervirens. The opposite, bird-feather-like rows of half-inch-long small leaflets are beautiful softgreen; they turn apricot before falling off in autumn, together with the annual twigs. Cones are up to an inch in size. The tree will take to any well-drained soil, or even wet soil, but loves regular moisture; it is not a tree for dry spots. It will grow in a lawn, but eventually it may develop surface roots. It does not like desert heat or salt air, and is resistant to oak root fungus.

A few cultivars are available: the bright green "Emerald Feathers" and the narrow, conical "National."

-- Pieter Severynen

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Photo: Pieter Severynen

Tree of the Week: White Sapote

 

The White Sapote -- Casimiroa edulis

"Zapotl" is said to signify any "soft sweet fruit" in the Nahuatl language of the Nahua Indians from Central Mexico. "Cochitzapotl," their name for the subtropical white sapote native to that area, means "sleepy sapote"; soporific and medical qualities are claimed for the fruit. A mature tree may produce hundreds of pounds of fruit per year, with custard-like consistency and mild banana/peach flavor. Since the fruit bruises easily it has remained a specialty crop but it is grown commercially on a limited scale. The tree thrives wherever lemons are grown. Hundreds of devoted California Rare Fruit Growers treasure one of the many grafted varieties in their gardens; see their publications or the "Fruit Gardener" for additional information.

The white sapote or custard apple is a beautiful evergreen tree that grows fairly fast to 25 to 50 feet tall and one-half to two-thirds as wide. The right choice of variety and some judicious pruning will keep it much smaller. Seedlings may grow fast and large, but may bear later in life and have less desirable fruit than grafted varieties. The smooth bark is grayish white, the branches may droop a little and the wood is brittle. Shiny green leaves are palmately (hand-shaped) compound, with about five 5-to-6-inch-long leaflets.

After a six- to nine-month ripening time, the small, greenish yellow flowers develop into apple-size green to orange-yellow, round to irregular fruit. Ripening time starts about October in the Southland; some varieties bear year round. To prevent bruising, the fruit should be harvested with a piece of stem attached; keeping the tree away from paved areas makes it easier to deal with fruit drop. The tree dislikes dry desert heat and tropical humidity. It prefers soils on the acid side but will take most soils that are well drained; it is drought-tolerant but performs better with occasional to regular deep watering. Roots are greedy; they are best contained.

Franciscan monks introduced the tree to California around 1810. The white sapote is located in the Rutaceae family; it is very distantly related to citrus. Many other fruit trees that go by the name sapote belong in different genera.

--Pieter Severynen

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Photo: Pieter Severynen

Tree of the Week: Cork Oak

The Cork Oak -- Quercus suber

Cork grows as a thick protective layer of outer bark, much thicker in the cork oak than in any other tree. Strange as it is to see a stripped cork oak with its lower 12 or 15 feet of dark inner bark exposed, the cork can be safely hand-harvested every 10 years or so as long as the underlying cambium is not damaged.

Cork, which is the oak's way to protect itself from a harsh environment, has unique properties: it is very light, resilient, waterproof, fire retardant, abrasion resistant, insulating, buoyant, and a poor conductor. The cork oak is native to the Western Mediterranean and North Africa. Portugal produces half the world's cork supply; it started protecting the trees in the 13th century and has developed a unique half wild production landscape.

A fairly fast grower, this evergreen tree initially grows taller than wide; eventually it becomes 30 to 60 feet tall and wide. It may live to 250-plus years old. Light gray, thickly fissured ridges cover the trunk and the heavy limbs. The cork oak tends to form co-dominant (i.e. equal thickness, competing) upright trunks. Three- inch-long leaves are toothed, oval, dark green above, gray green below. Inconspicuous flowers develop into short pointed acorns, three-quarters to 1 1/2 inches long, sitting in bowl shaped caps.

The tree tolerates many garden conditions, including drought and desert environment, but it wants full sun and good drainage. 

Cork is an excellent bottle stopper material: its suberin, a natural waxy substance, makes it impermeable to gas and liquids and prevents it from rotting. Cork stoppers were found in Egyptian tombs. In 1688 Pierre Perignon found the material unsurpassed to seal champagne bottles with. But screw tops and plastic stoppers may soon make cork obsolete for this purpose; then the greater half of the cork industry and the way of life that depend on it may simply disappear.

--Pieter Severynen

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Photo: Pieter Severynen