Palms and Cycads Beyond the Tropics
150 pages, 180mm x 245mm
Palm and Cycad Societies of Australia (PACSOA)
Finally a good little hand-book for cool climate palm and cycad growers. Not only is it useful for higher latitude locations, but also for high altitudes in the tropical regions where coldhardiness is an important consideration.
A good range of palms and cycads able to tolerate some degree of cold are discussed. The palm genera Butia, Ceroxylon, Chamaedorea, Livistona, Phoenix, Sabal, and Syagrus being covered in most depth. Of the cycad genera, Dioon is particularly well represented; other genera of cycads receiving detailed attention include Encephalartos and Macrozamia . The material is well researched and presented in a very readable manner. This book may not yield much new information to the enthusiast, but it does bring together most popular current information into an easily accessible format.
The photographs are certainly a bonus, particularly for a book in this price range. They cover an excellent range of species, habitats - both wild and under cultivation - and growth stages. Some of the photographs are particularly interesting as they depict species, some of which are relatively new to cultivation, in their native habitats, such as the Ceroxylon species. These types of photographs are a useful insight into both their growing requirements and potential size.
The sections on cultivation form a practical guide, covering germination, the raising of seedlings, procedures and considerations of planting out in-ground, and the nutrient requirements of both palms and cycads. Fortunately this is an area of the book where palms and cycads have been segregated. Although landscape-wise these plants are used similarly, they do have very different cultural requirements particularly in the germination and seedling stages.
There are important points made on palm seed viability including that rainforest species have a shorter viability than those from drier environments. Another useful point discussed is the inappropriateness of sowing cooler climate seeds in temperatures better suited to tropical growth. Seed sowing and seedling care and management are all well covered with such useful points as the use of sterile propagation medium, nutrition for seedlings and care needed with seedling roots discussed. A thorough section on planting-out in the ground from soil preparation, through watering, the all important site selection and finally mulching rounds off the chapter on palm cultivation. However, some care is needed in interpreting some of the mineral deficiency information, in particular the references to alkaline soils, as most nutrients are unaffected until a pH in the range of 8.0 to 8.5 is reached. (Many palms grow unaffected in a pH of 9.0 or more including Butia capitata , Phoenix canariensis , Trachycarpus fortunei , Washingtonia robusta and W. filifera ).
Cycad cultivation is also well covered. The discussion on seed sowing, checking for viability and germination is concise and thorough. Planting media requirements are discussed and a medium used by the author is given. This seems adequate as there are probably as many recipes for cycad mediums as there are for potted orchids.
Light as a growth factor is also discussed, as is the foliage colour being an indicator of a cycad's light requirement. For instance, blue or glaucous leaflets indicate the plant will tolerate high light levels, while deep green leaflets suggest a more protected environment is required. The discussion on cycad fertilizer requirements is brief and adequate as there is still little information available. However, as stated in this section... 'there is a concensus... that cycads require fertilizers higher in phosphorus and potassium than most foliage plants and lower in nitrogen ..."
Another section of the book which for many people will become well-thumbed is the species selection table. Landscape architects and garden designers of all levels will find this a useful guide for choosing palms and cycads for specific sites. Each species discussed in the book is listed on one axis of the table. The other axis can be used to find form, size, various climate categories, and siting information, such as sun-hardiness, and suitability to coastal planting.
The section on climate data is useful and the climatic classifications are easy to interpret and compare. Comparisons are drawn between cities under the same climate classification; for example San Francisco, Santiago, and Melbourne are all cool Mediterranean. This is useful but still must only be considered a guide. The climate discussion not only covers frost and cold as injury factors, but also lack of summer warmth as a restricting factor to adequate growth for recovery from damage.
It should also be realized that just because a species fits under the constraints of a particular climate zone, it does not necessarily mean that it will make a worthwhile horticultural or aesthetic specimen in all microclimates of that zone. As the author states in that section... 'it is important to understand the micro-climates of your garden ...'.
Depending on your motives as a grower, a decision should be taken whether it is worthwhile to grow a plant merely as a botanical representative or to select a species, regardless of how commonly prevalent it is, that has the potential to develop into a choice specimen. As all good gardeners have known since the beginning of gardening itself, it is more efficient and a successful outcome is more assured if a plant is chosen based on its suitability to the intended growing site. This book will help those individuals with limited time and resources to sort palms and cycads into those species which are worth growing within the constraints of cold temperatures or mild summers.
Contributed by: Julie and John Roach (from Palms & Cycads No 37, Oct-Dec 1992).