Each year, The Arboretum at UC Santa Cruz, (UCSC) works closely with growers in Australia and here in California to introduce new plants through a unique program called Koala Blooms. In this collaborative effort, many impressive Australian plant cultivars are evaluated for their beauty, durability in landscape situations, potential for invasiveness, performance in nursery conditions, and sturdiness with regard to drought, weather extremes, and soil pathogens. From all the choice plants selected and trialed, only a few are introduced each year. The program generates a small income to support the Arboretum.
The Koala Blooms program has its roots in the mid-1970s, when Rodger and Gwen Elliot, of Melbourne, Australia, sent their first shipment of Australian plants from their Australian native plants nursery to the UCSC Arboretum; plants have been arriving ever since. The enthusiasm for native plants has attracted Australians to the California countryside and Californians to the Australian bush. Countless longstanding friendships have emerged through all of this horticultural interaction. The Koala Blooms Introduction Program stands on the shoulders of these friendships and international exchanges.
Originally discovered on a point of land along the southern New South Wales coast near Ulladula, Banksia spinulosa ‘Schnapper Point’ is a low-growing, compact selection of hairpin banksia that will grow two to four feet high and four to five feet wide. Typical selections of this species reach the height of a small tree, so ‘Schnapper Point’ is distinct and makes a dependable shrub for full sun or light shade in relatively well-drained soils. Though tolerant of drought, it benefits from a little supplemental water during the dry summer months; in its native haunts along the NSW coast, there is occasional summer rainfall as well as intense drought. Handsome honey and red, candle-like flowers top the branches from fall through the winter months and into early spring. Like most members of the protea family, this banksia is sensitive to excess phosphorus in the soil, and needs little fertilizer. It should be hardy to around 20° F or possibly lower.
Correa pulchella ‘Pink Flamingo’ is a small shrub, only two to three feet high, with smooth, shiny, deep green leaves on a dense branching habit. Its deep, salmon pink, bell-shaped flowers are striking, both up close and from afar; the flower color can change as the flowers age and, at first, fooled us into believing that a sport was appearing on an established plant. The flowers appear in the middle of winter and last through late spring. ‘Pink Flamingo’ is from the coastal region of South Australia, where it grows on alkaline soils, unlike many Australian plants that require acid soil conditions. Relatively good drainage is still recommended. It grows well in dry shade beneath native oaks and is said to be deer resistant. So far, we know it is hardy to the mid-20s F.
Grevillea lanigera ‘Coastal Gem’ is a fantastic low spreading, woody ground cover with crowded, narrow, grayish green hairy leaves on prostrate stems. It has proven to be a sturdy and dependable groundcover and is already widely used in landscapes throughout much of coastal California. It grows to about one foot high by four feet across. The pinkish red and cream flowers are attractive in tight clusters at the ends of branchlets. Flowering starts well before Thanksgiving and lasts past St Patrick’s Day, perhaps through April. ‘Coastal Gem’ needs acidic to neutral soils for best results. It is excellent for general planting, in rockeries, and as an edging. It is hardy to the high teens or low 20s F and attracts hummingbirds.
Grevillea lanigera is called the woolly grevillea and has a wide natural distribution, from eucalypt woodlands and forests to subalpine habitats and coastal heathlands. Although ‘Coastal Gem’ is a coastal selection and tolerant of coastal exposure, it has shown itself to be true to its species and widely adaptable.
Pink-flowered Boronia crenulata ‘Rosy Splendor’ is a compact evergreen shrub growing to three to four feet high and about as wide. It is particularly appealing during late winter and spring, when it is encased in masses of flowers. Its light green, oval leaves are highly aromatic. It performs best in full sun to part shade. Like many Boronia species, it is not a total drought lover, although this species is much sturdier than most. It is best to water during dry periods and to avoid overhead sprinkling during hot spells. ‘Rosy Splendor’ is excellent for rockeries, borders, and in large containers. Native to western Australia, it has proven hardy to the mid-20s F.
Correa ‘Ray’s Tangerine’ is a vibrant orange selection with narrow bell-shaped flowers appearing in fall and through the winter. This cultivar was hybridized by founding UCSC Arboretum Director Ray Collett, who has yet to divulge the whereabouts of its parents. Although it is a little slower growing than other Correa cultivars, it is well worth waiting for. It has shiny dark green leaves and grows eventually to two feet. It performs well in full sun or partial shade, with good drainage, and is tolerant of drought but does best with regular water during long dry periods. It is hardy to 20°F.
Bottlebrushes are common along California’s freeways and in our gardens, but none match the delicate beauty of Callistemon ‘Cane’s Hybrid’. This is an evergreen shrub or small tree (ten feet by five to eight feet) with a profuse display of pastel pink bottlebrush flowers during late spring and early summer. It has narrow gray green leaves on spreading, often arching branches. The young foliage is soft and tinged with pink. ‘Cane’s Hybrid’ is excellent for screening, for windbreaks, and for hedging. Drought-tolerant once established, it responds well to pruning and is frost-hardy to at least 20°F.
Chorizema ‘Bush Flame’ is a vining shrub that contributes a lot to a garden. Its brilliant, orange and pink, pea-like flowers are intense and long lasting, appearing from fall through early spring and sporadically all year. An evergreen for sun to light shade with good drainage and occasional water during the long summer, it can be used in rockeries, borders, large pots, and hanging baskets. It is frost hardy to the low 20s F.
Grevillea ‘Granya Glory’, a compact, low spreading, evergreen shrublet, presents clusters of rose red and cream flowers at the ends of branches in winter and early spring. Growing one to two feet tall by two to four feet wide, it has blue green, hairy, oblong leaves. It is excellent in rockeries and borders, preferring sun or partial shade and good drainage. Drought-tolerant once established, it is hardy to the upper 20s F.
Brachysema praemorsum ‘Bronze Butterfly’ has been described as a “Berkeley kind of plant” due to its weird chartreuse-edged, dark bronzy purple leaves. It is a prostrate creeper or slightly mounding ground cover. The pea-shaped flowers appear in spring, are initially cream, and then age to deep red. It grows best in full sun on the coast, but needs part shade inland, and appreciates water during dry periods. It responds well to shearing and is frost-hardy to the mid-20s F.
Found at Carpenter Rocks in South Australia, Correa reflexa ‘Carpenter Rocks’ is a choice selection, growing three to four feet tall and wide, with small, clasping, heart-shaped green leaves. The bell-like flowers are bright vermilion red, tipped with chartreuse and appear profusely from fall through spring. It thrives in full sun to partial shade, with good drainage, and is drought tolerant once established. Like most of the correas, its nectar-rich flowers feed the local hummingbirds through the winter. It is hardy to the mid-20s F.
Correa pulchella ‘Pink Eyre’ is a compact, evergreen shrub to three feet tall and about as wide. It has dark green oval leaves and is loaded with rosy pink, tubular flowers, which begin in fall and last well into spring, The heaviest bloom occurs during the winter months, when ‘Pink Eyre’ can magically ignite a dreary and somber winter scene. ‘Pink Eyre’ hails from the Eyre Peninsula on the coast of South Australia, where it grows on limestone. It will perform well in full sun or partial shade and is a superb plant for a container on a porch, deck, or patio. It is drought tolerant once established and is hardy to about 20°F.
Phebalium frondosum ‘Elizabeth’ is described as a narrow endemic from the Gippsland area of eastern Victoria, in southeastern Australia. There it grows on Mt Elizabeth in “loamy or skeletal soils” (according to Rodger Elliot). In the Arboretum, it is a narrow, upright shrub to six feet or more, with oval green leaves that are silvery on the underside. Small, starry white flowers sparkle against the foliage from late winter into spring. Useful as a hedging plant, both its foliage and flowers have a spicy-fruity fragrance. In sunny California it performs best in partial shade and in well-drained soils; it should be hardy to 20°F.
Tetratheca ericifolia ‘Heathland Gem’ is a dazzling jewel from central New South Wales, where the species grows in sandstone regions as a member of the heathland communities. It is an evergreen perennial with upright stems to about two feet tall, clumping to eighteen inches in diameter. It offers nodding, vivid pink flowers in profusion, starting in early spring and lasting into summer. Planted in full sun and given excellent drainage, it will appreciate some water during extended dry periods and is hardy to the mid-20s F.
An evergreen flowering shrub related to the correas and boronias, Philotheca (syn. Eriostemon) verrucosa ‘Starbright’ grows three to four feet high and about five feet wide. Its leaves and branchlets are covered with “warty” aromatic oil glands emitting a strong and powerful fragrance. Its pink buds open to pale pink starry flowers and bloom profusely from late winter to early spring, with scattered flowers throughout the year. Frost-hardy and drought-tolerant, it makes an attractive container plant. It will grow in most soils but is not recommended for alkaline conditions.
Boronia clavata ‘Heather Wand’ is an unusual shrub that grows from five to eight feet high and five to ten feet wide, with slightly hairy, pinnate, aromatic leaves. The attractive, delicately perfumed, bell-shaped flowers are pale yellow green and spring from the leaf axils along the stems; flowering is from late winter through early spring. This selection responds well to light pruning and needs acid to neutral soils for best results. It will withstand periods of dryness but needs some irrigation during the driest summer months. It is an excellent shrub for any garden as a border plant and as a low screening plant. It should be hardy into the mid-20s F or lower.
Another coastal plant adapted to salty sea air is Correa alba var. pannosa ‘Western Pink Star’, a low spreading, evergreen shrub to eighteen inches tall and three feet or more wide. Its leaves and stems are covered with felt-like, grayish white hairs. Its delicate pink, four-petalled flowers appear heavily in spring and early summer and last into the fall. It will thrive in partial shade to full sun, with fairly good drainage. Once established, ‘Western Pink Star’ correa will tolerate our long dry summers, although a monthly irrigation is beneficial. It is hardy to at least 28° F and possibly to 25° F
Formerly known as ‘Uncle Jack’s Red’, Boronia megastigma ‘Jack Maguire’s Red’, is a seedling variant of brown boronia that was selected in 1928 by the late Jack Maguire from the town of Boronia, Victoria. This is a superb, deep orange red color variation and possesses most of the marvelous characteristics of this species, especially the mysterious and alluring perfume that swirls and sweeps invisibly through the garden, far from the flowering source. There is nothing quite like brown boronia.
‘Jack Maguire’s Red’ is an upright shrub to three or four feet high and four to six feet wide. The narrow leaves are almost needle like; the pendant, bell-shaped flowers approach one-half inch in diameter. It grows best in well-drained, slightly acid soils that neither dry out entirely nor become soggy. It prefers dappled shade and will tolerate cold temperatures down into the low to mid-20s F. When the first flowers open in mid-February and release the wonderful perfume, you will be happy you added this boronia to your garden.
With each purchase of a Koala Blooms plant, a small royalty comes back to the UCSC Arboretum to support the Australian Gardens; a percentage of the royalty also goes to Australia in support of the growers who were responsible for the initial selection or breeding of each plant. Koala Blooms plants are available through Norrie’s gift shop at the UCSC Arboretum and through retail nurseries. Participating wholesale nurseries responsible for helping this program succeed are: Monterey Bay Nursery, Native Sons Nursery, Perry’s Panorama, Rosendale Nursery, San Marcos Growers, and Suncrest Nursery. The UCSC Arboretum is happy to receive so much support from these wholesale nurseries, from the Australian growers, and from plant lovers who purchase these superb new plants.