This blog reviews the latest products, plants and innovations in gardening. It also provides a link for my many gardening friends who are members of the GardenMessenger and Seedmessenger Yahoo groups and their sub-groups that I moderate.

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Location: Australia

I am a semi-retired UK botanical garden curator and former international horticultural consultant, who has worked extensively in Europe, the Middle East, North America and Australia. I spend part of the year in Australia and part in Europe, mainly due to family and work commitments. I earn my living from writing and editing Internet copy, articles and books. I have written over fifty books on gardening and have been translated into twenty-four different languages. I am a former UK Garden Writer of the Year and a previous Quill & Trowel Award Winner from the Garden Writer’s Association of America. I am interested in developing gardening communities on the Internet and I manage the popular GardenMessenger Yahoo group, along with its various sub-groups like PondMessenger and SeedMessenger. I also edit International Water Gardener and its associated regional web-sites.

Friday, April 28, 2006

Cotoneasters, Raising Ferns from Spores, News and Diary

Join OrganicGardenMessenger

My wife Hazel was right about the popularity and need for the
OrganicGardenMessenger group. Since launching it yesterday over 60 members have signed up. When a group first goes online it is not generally visible to the public for a couple of days and so it has very limited exposure. The great thing too, is that folks are busy discussing things and already making new friends and contacts. What a great medium the Internet is for communication. If you missed yesterday’s link and want join click here

The other day I mentioned the use of Cotoneaster as a ground cover plant, and then went on to qualify its suitability by saying that it sometimes got a bit taller than expected. Since then I have been asked to give a brief review of species and cultivars that might be useful for ground covering by Tony and Rosemary in the UK. They think that they are great in the cold northern parts of the country and are just starting a large new garden with plenty of space to fill.

Cotoneaster horizontalis

The most commonly grown, and the one that I believe is the most versatile is the Herringbone Cotoneaster, Cotoneaster horizontalis. It is an ideal plant for difficult banks and slopes. It has a herringbone pattern of branches arranged with mathematical precision, and these are clothed with small rounded leaflets. In the autumn both the foliage and the berries turn vivid red. The fruits are persistent long after the leaves have fallen. In smaller areas, or those that are reasonably level C.microphyllus is a good alternative. A dwarf stiffly-branching, spreading shrub it has oval or elliptical evergreen leaves and tiny white flowers followed by deep reddish-pink fruit. However, the best Cotoneaster of all is the ground-hugging ‘Gnom’, a prostrate form of the common garden shrub C.salicifolius This completely carpets the soil in glossy evergreen foliage and is sprinkled in autumn with bright red berries. Cotoneaster salicifolius 'Repens' is very similar.

Cotoneasters prefer a medium to heavy soil. They can be planted at any time from containers providing that they are well-watered, but also bare-rooted during the winter months. Propagation is by short stem cuttings taken with a heel of old wood and rooted in an equal parts mixture of peat and sharp sand in a cold frame during late summer. As cotoneasters are very promiscuous, seedlings produced from seed gathered from plants in the garden at home can be very variable. Even those raised from purchased seed have some variation. Planting distances are dependent upon the species or cultivar and the speed of cover required. Occasional pruning to keep the plants in order is necessary during the growing season and a slow release fertilizer administered each spring is beneficial.

Ferns are seeing a great revival, especially for the garden and landscape. They have always been popular as houseplants, especially in those gloomy corners where nothing else will grow, but the frost-hardy species have long been neglected. I love the bold Dryopteris, both the European and North American species. They are great architectural plants for almost anywhere in the garden. Not only are they easy to grow, but quite easy to propagate from either division or spores. Dividing plants disrupts the planting and should only be done when necessary for the plant’s well being. They can all be increased from spores and this, as with many other fern species is not a difficult task providing that a little of their life history is understood.

Spores are produced in clusters of sporangia

Spores are not, as is commonly believed, the fern’s equivalent of seed, but are comparable with the pollen grains of a flowering plant. The adult fern as we know it is asexual – neuter – and produces clusters of sporangia which contain the spores on the backs of their fronds – or leaves. These appear as mounds of black or brown dust and in nature they rupture, to cast clouds of viable spores into the wind. On reaching a suitable surface they germinate and produce a curious triangular-shaped green scale-like growth called a prothallus. When mature these tiny prothalli develop male and female organs on their undersides. Then the resultant male gametes – or sexual reproductive cells – fertilize the female ones. After this stage the fern as we know it grows and develops with recognisable fronds.

Spores that are ripe and suitable for sowing will disperse as a dusty cloud when a frond is lightly tapped. These can be collected by enclosing the whole, or a sizeable portion, of the fertile frond in a large paper bag, breaking the frond stalk, and then up-turning it in the bag. Given a vigorous shaking, the ripe spores will detach themselves from the fruiting body and collect in the bottom of the bag. A different bag must be used for each species because some of the dust-like spores will almost certainly remain behind after each operation.

There are several methods of raising spores, but one of the simplest works admirably with all the ferns likely to be encountered by the average gardener. Well-scrubbed and sterilized pans are filled with a sterilized compost of three parts by volume of peat, one part loam. To each household bucketful of this add three teacups of crushed charcoal (activated filter carbon from the pet store is fine). This helps to keep the mixture from becoming sour. The whole surface area is then covered with a layer of clean, finely crushed brick dust and the spores are sprinkled thinly on this in the same way as one might sow lobelia or begonia seed. A small square of glass is laid over the top of the pan, which is then placed in a saucer of water, depending upon species or cultivar, in a warm, partially shaded position in either a greenhouse or closed frame.

After about three weeks, depending upon the species and temperature, the tiny prothalli will begin to smother the surface of the pan, appearing as a creeping mossy growth. It is imperative at this stage that the saucer be kept continually full of water, for drying out of the soil surface at this crucial time, if only for a few hours, will ruin or greatly reduce the chances of success, for fertilization only takes place only when there is a film of water on the soil surface.

Eventually minute fronds will appear amidst the mossy growth, and the glass should be removed to allow the air to circulate freely. The young ferns should remain in the pan until they are sufficiently large to handle comfortably, when they can be pricked out in clumps into a compost of equal parts peat and loam and then placed in a cool, moist, airy position. They can remain like this until growing strongly, when they should be lifted and the individual plantlets teased out of the clumps and
pricked out singly.

Most ferns are comparatively easy to raise in this manner, but the spores of the various Osmunda species should always be sown immediately after collection, for these contain a small quantity of chlorophyll, which renders them viable for only a few days. Sometimes a fern proves to be temperamental and difficult to raise in this manner. Particularly some of the more sophisticated warm greenhouse species. Often ferns which had earlier failed to germinate, will do so quite freely if sown on the surface of the fibrous rootstock of an adult growing specimen of the Bird’s-nest Fern, Asplenium nidus. Maintaining a plant or two of this species for this specific purpose is very useful.


A New Botanical Garden for China
The Chinese Academy of Sciences and the Beijing municipal government are planning to build a world-class botanical garden. At a meeting last week to mark the 50th anniversary of the establishment of the Beijing Botanical Garden, Han Xingguo, director of the Chinese Academy of Sciences (CAS) Institute of Botany, announced that they have received approval to build the national botanical garden which will be combined with the existing Beijing Botanical Garden.

New Hibiscus
The lovely new perennial Hibiscus 'Mauvelous' is a cultivar of H. syriacus with some H. moscheutos parentage for hardiness. It grows approximately 1 m (39 in.) tall in the garden, slightly lower when used in a container. It produces large, 20-30 cm (8-12 in.) warm pink flowers with dark centres.

Potato Cyst Eelworm Reported The USDA has reported that there have been two finds of Potato Cyst Nematode in State of Idaho. The Canadian Food Inspection Agency has implemented a temporary prohibition on the import of all potatoes and soil from the State of Idaho due to this detection more.

Royal Flora Ratchaphhruek 2006
1st November-3rd January

Royal Agricultural Research Center,
Chiang Mai,
Details click here.

Happy Gardening



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