Plant Notes

April 2008 Plant Notes

Aeonium arboreum (CRASSULACEAE) 
Grown by Chris Todd in Sunnyvale:
The species is native to the Moroccan coast and has green leaves. Most retail plants are garden-origin hybrids. They are evergreen, bushy succulents forming clumps of bare stems topped with 8"-12" wide rosettes of fleshy leaves. In spring, large, dense pyramids of light yellow flowers rise from the rosette centers. They need excellent drainage, deep infrequent water, and prefer cool sun to light shade. Sun intensifies the color of the dark-leaved forms. They should be hardy to ~28°F. Chris brought A. a. 'Zwartkop' which grows as a 3'-4' x 3'-4', open, airy clump and has particularly dark maroon, almost black, leaves. Confusion surrounds the origin, name, and parentage of this plant and whether or not most nursery plants labeled 'Zwartkop' actually are. She also had a Jack Catlin hybrid with green-eyed, burgundy rosettes and a tight, dense growth habit to 2' high x 4' wide.

	Athrotaxis cupressoides (CUPRESSACEAE) Tasmanian Cedar, Pencil Pine

Grown by Kerry Barrs in Woodside: 
A distant relative of our Sequoiadendron, Athrotaxis is endemic to mountain forests of western Tasmania where it grows around lake shores. It is a small, ~35', narrowly conical, evergreen conifer. The leaves are small, bright green scales that overlap each other and are tightly pressed to flexible, "whippy" stems. Overall, the tree has a soft, fluffy look and would be a beautiful landscape tree in areas with high rainfall and cool summers. It is a slow grower and lives well over 1000 years. In Tasmania, it is threatened due to fires and the slow pace of its regeneration.

Berberis valdiviana (BERBERIDACEAE)
Grown by Betsy Clebsch in La Honda: 
Betsy bought this Chilean native from Heronswood Nursery 8 years ago. It has glossy, dark green, nearly spineless leaves. The stems still have plenty of spines though. Even so, Betsy recommends getting in there and giving all barberries an occassional hard pruning. This barberry blooms in spring with long, dense, drooping clusters of globe-shaped, saffron yellow flowers. It has a rather open habit and can grow to 15' x 15'. There seems to be agreement that it is difficult to propagate, so it's not likely to become a common sight in nurseries.

	A Celebration of California

Grown by Liz Calhoon in Los Altos Hills: 
Liz had just returned from vacation, had fallen in love with California all over again, and wanted to share some of the reasons. She brought some California Poppies, of course, and stems of: Quercus chrysolepis (Canyon Live Oak) with its small, ribbed leaves with prickly edges; Salvia leucophylla 'Point Sal Spreader', the low, spreading (2' x 8') form of Purple Sage with silver foliage and whorls of rose-pink flowers; and Ceanothus griseus v. horizontalis 'Yankee Point', a 2' x 10' mass of glossy green leaves covered in masses of medium blue flowers late winter through spring.

	Citrus medica v. sarcodactylus (RUTACEAE) Buddha's Hand Citron

Grown by Kris Mongtague in Los Altos: 
Buddha's Hand probably originated in northeastern India, may have been the first cultivated citrus, and first made its way to Europe during the Greek and Roman empires. It's a small, thorny shrub to 6' tall with rumpled, dark green leaves. The unusual fruit looks like a large, rough-skinned lemon that decided to segment into several pointed "fingers". It is all rind with little or no pulp and no seeds, but with a nice lemon scent and taste. My nose thinks there's a floral tone as well. The dried fruit has long been used in Asia to scent rooms and clothing. It is also used for zest, it is candied, used for marmalade and anywhere else lemony flavor is called for. Since the pith is not bitter, the whole thing can just be sliced thinly. It blooms all year but the spring flowers produce most of the fruit, which ripen mainly in winter. It will not tolerate frost.

	Clematis x cartmanii 'Avalanche' (RANUNCULACEAE) White Evergreen Clematis

Grown by Dick Dunmire in Los Altos: 
This relatively new (1999) introduction was bred in England and is a hybrid of two New Zealand species, C. paniculata and C. marmoraria. It's evergreen with foliage that resembles leathery, glossy Italian parsley. In spring, it absolutely covers itself with clusters of 2 ?", white flowers. They usually have 6 tepals that open flat with prominent yellow stamens in the center. It takes full sun to light shade, requires average irrigation, and is winter hardy into the teens. It can be a 12'-15' vine if trained on a support or use it as a groundcover. Dick's came from Trader Joe's, trained on a little hoop, but has become glorious since Dick set it free. 

Echium gentianoides (BORAGINACEAE) Mountain Blue Bugloss
Grown by Betsy Clebsch: 
From Annie's Annuals, this is a rare and endangered Echium endemic to the pine forests on La Palma Island in the Canaries. It is a branching, low, woody shrub that can grow to 5' tall but is more often around 3 ft. It has long, broad, glossy, blue-green leaves. From late winter into spring, it puts up big spikes with lots of 1", tubular, gentian blue flowers.The throats, buds, and calyces are deep magenta. It prefers full sun, low water, and relatively inorganic soil. Betsy's survived 27°F last winter. 

Heuchera micrantha 'Martha Roderick' (SAXIFRAGACEAE) Small-flowered Alumroot
Grown by Betsy Clebsch: 
Wayne Roderick introduced this pink-flowered form of our native alumroot and named it for his mother. The species is common in our forests where it's easy to recognize its purple-veined foliage with gently ruffled edges and subtle marbling. 'Martha Roderick' is a compact, 8"-12" foliage clump that stays neat all year. From spring into summer, slender, 2' tall flower stems bloom with masses of tiny, deep pink flowers. Their airy appearance is very pretty in the woodland garden. They are drought tolerant, but better with occassional water.

Melianthus major (MELIANTHACEAE) Honey Bush
Grown by Kris Montague: 
This is a bold, evergreen, soft-wooded shrub native to South African grasslands. It can quickly become 8'-12' tall and wide and spreads by suckering roots. Light bluish-green, 1'-2' leaves are divided into sharply toothed leaflets that fold upward a little along their midveins. They have a strong, unpleasant smell when brushed or bruised. Foot long, terminal spikes of reddish-brown, 1", tubular flowers bloom spring to summer and are loaded with nectar. It is a dramatic, tough, easy plant for sun or part shade and moderate irrigation.

Salvia carduacea (LAMIACEAE) Thistle Sage
Grown by Sally Casey in San Jose from seeds collected along Shell Creek Rd.:  Hands down, this annual has the world's most beautiful salvia flower. Stems to 20" tall have 1-4 whorls of large, lavender-blue flowers with fringed edges and 2 orange anthers. They are held in white, densely woolly calyces with sharp spines. They grow in Contra Costa County and south in dry sandy or gravelly places in chaparral, desert, and coastal scrub.

Thuja plicata 'Filifera Nana' (CUPRESSACEAE) 
Grown by Kerry Barrs: 
Kerry's arborvitae is a very unusual, dwarf form of Western Redcedar. It's upright stems end in long, tread-like branchlets. Scale-like leaves are pressed tightly to the branchlets. If it can stay away from deer, who love arborvitae, it should become a dense, 4' x 4' mound with a weepy, arching habit in about 10 years. It prefers sun or a little shade and average water. 

Jackie N. Doda

References: Am. Hort. Soc. A-Z Encyclopedia, Botanica, Flora, Sunset Western Garden Book, and various websites.