Cultivation Of Kangaroo Paws
The following is from the 1991 Australian Plant Symposium University of California, Santa Cruz by Randy Baldwin, Horticulturist and General Manager of San Marcos Growers.
The culture and care for many of the Kangaroo Paws is fairly easy if a few of their basic requirements are met. Merv Turner, the hybridizer responsible for the Bush Gem series wrote an article in the August 1986 publication of the Australian publication Gardenscene. He set down the following 5 rules for the cultivation of Kangaroo Paws.
- Plant in a sunny and open position in the garden. If in a frosty area, plant under eaves on the south side of the house or under a high tree canopy.
- Provide these plants with excellent drainage.
- In summer dry climates provide these plants with regular water (providing the drainage is good) to keep plants evergreen.
- Fertilize, but not heavily, and keep Phosphorus on the low side.
- Annual clean up. After the flowering period remove the old leaves down to as low as possible. Fans only flower once and need to be cleaned out at the end of a season. Care should be exercised that the new emerging fans are not damaged.
Although plants can be established at any time of the year, it is best to plant during the cooler months: either late in the fall or in early spring. If one is planting in a location where medium frosts are expected, protect plants with mulch or wait until spring to plant. A sunny position in the garden is generally best although many of the species and hybrids will grow and bloom in an open light shade. If the location suffers from hard frost, plant in a sunny spot under eaves or under the protection of a tree canopy. Kangaroo Paws do best in, and in fact some will tolerate only well drained soils. A. flavidus, the most common species in cultivation in the US, and parent to most of the common hybrids, tolerates heavier soils than the others, but still responds to more favorable conditions. It is reported that A. manglesii and rufus also will take heavier soils and that all three tolerate seaside conditions.
Summer irrigation seems to shorten the life span of Kangaroo Paws, for all species except A. flavidus, yet many of the hybrids will look best if given ample water until the flowering period is over in late summer. Many of the species come from areas of prolonged summer drought and will tolerate similar conditions in cultivation; these species tend to be summer dormant and are easily rotted if given water once in dormancy. For the best production of flowers the cut flower industry in Australia has been advised by their Agricultural Department to drip irrigate on sandy soils daily during the summer. A fertilizer can be supplied through irrigation water. In California, cut flower growers keep stands evenly moist until flowering has finished in fall. In the landscape Kangaroo Paws can be irrigated in a different manner. A. flavidus, A. humilis, A. rufus, A. manglesii and A. pulcherrimus are all species that grow well in dry summer climates. Many of the better hybrids have one or both of these plants as parents and likewise can be treated in a similar manner. These plants can be grown with other Mediterranean climate plants in a dry, or infrequently irrigated garden. It is still advisable to use drip irrigation when irrigation is performed, as this lessens susceptibility to disease.
Flower initiation and bloom quality is best with healthy well irrigated plants. The Western Australian Department of Agriculture has noted that irrigated plants tend to flower on the average 1 month earlier than native stands. Flowering time can also be dependent on the planting time and method of propagation. Plants propagated from seed may take several years to flower where as division propagated plants will flower the first season. Plants propagated by tissue culture often will initiate flowering 6 months after planting the first year and will flower at the normal time the following season.
By far the most common and damaging problem involved in the cultivation of Kangaroo Paws is the dreaded Ink Spot Disease or Ink Disease as it is often referred to. It is thought to be the fungus Alternaria alternata. Ink Disease causes the blackening of the leaves and flower stems starting close to the leaf tip and progressing down to the rhizome. For some plants such as A. flavidus the disease appears to cause only cosmetic problems. It can be fatal to species such as A. manglesii and A. pulcherrimus. Prevention of Ink Disease is difficult since this fungi has air borne spores which are spread worldwide but by giving ample spacing for good air flow, the chance of infection can be reduced. Certain nutrient deficiencies, especially Calcium and Potassium can increase a plant’s susceptibility and physical damage to the leaves caused by human contact, frosts or by pests such as snails and slugs can increase the chance of infection. Heavy soils, humid conditions or heavy shade can also make plants more susceptible to this disease. It should be noted that many of theses causal agents can produce symptoms that both resemble and enhance the disease. If a blackening of the stem is noticed, look at it carefully to see if the pitting caused goes all the way through the leaf. Watch for the blackening to spread down the stem and rogue out badly infested plants. Several fungicides have been suggested to control Ink disease.
Kangaroo Paws can be affected by a number of other diseases, including a rust fungus on the leaves and root and stem diseases such as Phytophthora , Pythium and Fusarium. Plants are more susceptible to these diseases when under stress. Use of certain fungicides may control these diseases.
The most important animal pest to keep off of Kangaroo Paws is the European Brown Garden Snail. Besides eating leaf and flower parts, this snail can make plants more susceptible to disease. Aphids can become a problem in spring and fall but are easily controlled by washing them off the foliage or by the use of soaps or insecticides.
Indications of Nutrient Deficiencies
- Nitrogen – Plants produce pale green leaves; few fans are produced.
- Phosphorus (rare) – The older leaves of a plant develop an orange-yellow color and die back. Phosphorus toxicity is more common (especially evident in A. pulcherrimus and Macropedia) ; it appears like Ink Disease with blackened tips that gradually progress down the leaf blade.
- Potassium – The deficiency symptoms appear on the oldest leaves. The tips die and may be accompanied by brown spots on the outer half of the leaf. Plants are poorly anchored and topple when in flower.
- Magnesium – Plants develop a blue black discoloration on the upper half of the older leaves which progressively works its way down, creating a mass of dead leaves.
Anigozanthos - The Genus
In some books the Anigozanthos are called “sword-like” or “iris-like” but in fact they are a genus of plants in the Haemodoraceae, a family which is represented by 13 genera, primarily restricted to the southern hemisphere (Lophiloa – a small perennial bog plant is found in the eastern USA). There are 11 species of Anigozanthos, or Kangaroo Paws as they are commonly called, that are restricted to the southwest corner of Western Australia. They are rhizomatous herbaceous perennials with flat strap-shaped leaves that are folded at the midrib. The bird pollinated flowers are tubular and split lengthwise with the 6 lobed “claws” being on the upper side of the flower. Often theses flowers are brilliantly colored and are sometimes clothed by contrasting colored hairs.
Origins of The Name
The name Anigozanthos was assigned by French botanist Jacques de La Billardiere, but it has several possible derivations. Several botanical texts list it as a combination of the Greek words anoigo = to expand and anthos = flower which is in reference to the the flower being split. Other books list the meaning as the combination of the Greek words anisos = unequal and anthos = flower in reference to the irregular corolla. There have been several spellings listed for Anigozanthos including Anigozanthus and Anigosanthos. The genus has also been variously placed in the Amaryllidaceae from time to time by horticultural and botanical texts. Current nomenclature puts the Kangaroo Paws in the Haemodoraceae and has the spelling of the genus as Anigozanthos. Two genera that are closely related to Anigozanthos and grow in the same geographical area are Conostylis and Macropidia. Anigozanthos differs from Conostylis in that it has zygormorphic flowers and differs from Macropidia in its short staminal filaments and multiple ovules per cell. Intergeneric crosses have been attempted between Macropidia and Anigozanthos.
Introduction into Cultivation
Due to their unusual flower structure and striking coloration, the Kangaroo Paws have become desirable to gardeners and horticulturists throughout the world. This interest was first cultivated, as it often was with new and unusual plants, by the English. Louden’s Hortus Britanicus, A Catalog of a Plants Endemic, Cultivated or Introduced to Britain, written in 1830, states that in 1808 A. manglesii was introduced by Robert Mangles who had possibly received seed from his brothers in New Holland (Aust). Anigozanthos rufus was introduced into cultivation in 1824. The Royal Horticultural Society Dictionary of Gardening dates of the Botanical Magazine Plates are listed as A. flavida 1808 (BM 1151), A. manglesii 1833 BR, A. pulcherrimus (A. tyrianthinus) 1844 (BM 4507).
IN THE USA
The first reference of Anigozanthos in the US is made in the 1902 edition of Bailey’s Cyclopedia of American Horticulture which lists that “there are 8-10 species of Anigozanthos from Australia for the greenhouse or as half-hardy perennials.” Bailey further states that these plants are cultivated in Europe but unknown to the American trade. By the time the 1928 edition of Bailey’s was written, Anigozanthos had been upgraded to “Little Known in North America” but both A. flavidus and A. manglesii were listed. Bailey’s 1935 Hortus I lists Anigozanthos as an “odd Australian perennial herb with thick rootstocks, linear or sword shaped basal leaves and large red, purple, green or yellowish flowers borne in one sided wooly racemes or spikes, the perianth tube very long”, but only A. manglesii is described. Peter Riedel’s Plants for Extra-Tropical Regions, which was published after his death in the 1950’s, is an incredible work that documents much of the plant introduction work that took place in California around the turn of the 20th century. Although he states that there are few Kangaroo Paws to be found in California, A. manglesii was offered in catalogs in 1911 and again in 1920. He lists Bureau of Plant Introduction numbers for A. manglesii #81671 from 1930, A. flavida BPI #76931 – 1933, again 132069 – 1939 (possibly the red form?). Reidel also states that A. humilis was offered in catalogs in 1920 as was A. viridis.
Further introductions of Kangaroo Paws were spurred on by interest in hybrids being created in Australia, and recognition by gardeners and nurseries in California that these plants were attractive and grew well in California gardens. Sunset’s Western Garden Book, the barometer of what is an accepted plant in the western garden, lists Anigozanthos for the first time in their 1967 edition. Kangaroo Paws are listed as a garden plant with “striking tubular flowers”. The only species commonly grown at this time was A. flavidus. As the Kangaroo Paws became more popular, the search for the better and new cultivar began. For this the gardening public relied on nurserymen who were importing plants and seeds from Australia. Paul Hutchinson, at Tropic World in Escondido, was involved in the production of A. flavidus and A. manglesii from seed in the late 1960’s. A neighbor of Mr. Hutchinson, Mr. Fred Meyer, purchased what he considered the best selections from these seedlings to divide and plant out for a cut flower field, from which he was able to produce several thousand cut stems for sale by 1975. Mr. Meyer was also interested in several other species of Anigozanthos and by 1979 was having his best selections of A. rufus and A. pulcherrimus propagated by Oglesby Tissue Culture Lab. Shortly after this time Mr. Meyer introduced me to Kangaroo Paws when I first visited one of his production fields. Later he supplied A. pulcherrimus plants to me for a cut flower field in Santa Barbara. With his interest in Kangaroo Paws it was only natural that he would travel to Western Australia, bringing back with him numerous hybrids, including the first Bush Gems to be cultivated in the US. Some of theses hybrid Kangaroo Paws have also made their way into the nursery trade here. Several hybrids that he brought back were released for sale at the Huntington Gardens annual plant sale in 1985, including a very attractive A. pulcherrimus x flavidus. Mr. Meyer is also responsible for the release of a very good tall pink selection of A. flavidus which has erroneously gone under the name of A. ‘Pink Joey’ in the California nursery trade. The true A, ‘Pink Joey’ is a dwarf from of A. flavidus that only more recently was introduced into the United States and is in the Australian Nursery Trade. At San Marcos Growers we are currently producing 6 different Kangaroo Paws and are working on introducing several more later in 1991 (We list 15 in our 2006 catalog). We are grateful to Mr. Fred Meyer for the help that he as given us in this venture and for the plants that he has brought into cultivation.
Many other nurseries have had an interest and have introduced Kangaroo Paws into the trade as well. M. Nevin Smith of Wintergreen Nursery has grown more species than any other nursery I have contacted. He currently has in production A. bicolor, A. flavidus, A. humilis, A. rufus, and A. viridis. Daryll Combs, of Daryll’s Exotic Plants, in Carpinteria has propagated the Hopper Hybrids and several selections of A. flavidus by division and is currently offering them for sale. El Modeno Gardens Nursery was the first nursery in California to import the Bush Gem hybrids and continue to do so at this time. The Nurseryman’s Exchange began marketing the University Series as a florist crop late in 1990. The USDA began a project in 1983 on new Anigozanthos hybrids and research on their cultivation. This project is taking place at the USDA Agricultural Research Service, Florist and Nursery Crops Laboratory in Beltsville, Maryland.
Excerpted from http://www.smgrowers.com/info/anigozanthosTalk.asp