Looking After Established Ferns

Looking After Established Ferns

After the ferns are established, good cultivation consists of keeping down weeds and giving an annual or biennial topdressing with gritty leafmould seasoned with bonemeal. As ferns are largely surface-rooting plants, this topdressing is the most important part of maintenance. During the spring tidy-up, before topdressing, dead fronds should be removed as near to the crown as possible, using a sharp knife

Pulling away the dead fronds is safe enough in the case of Athyrium and Cystoperis and other deciduous ferns, but it is not advisable with Phyllitis and Polystichum, as their crowns may be damaged by pulling away old fronds.

In nature, ferns get an annual topdressing of fallen leaves, and the remains of their own old fronds helps to build up a surface mulch of humus. In the garden regular weeding tends to lower the soil level slightly, year after year; the lengthening rootstocks carry the growing points farther from the soil, so that a liberal annual topdressing is essential to maintain the soil level and provide fresh food material for the surface roots.

 Looking After Established Ferns When weeding, forking around the plants should be avoided, as this practice damages the surface- feeding roots, and a hoe should, for the same reason, he applied very lightly. Hand-weeding is the best method.

Chemical surface weedkillers should not be used for weed control among ferns, as there is a great risk of damaging the plants. It is far better to increase the number of mulches to smother the weeds when young.

After two or three years it may be found necessary to move some of the ferns which perhaps were planted too closely in the first place, so that they are encroaching upon one another and unable to show their beauty to full advantage. It is a simple matter to loosen the soil by going round the crowns with a large fork, keeping well away from the crown at first, gently rocking the plant until it becomes easy to lift the clump with undamaged roots. If several plants are to be lifted, it is wise first to make provision for laying them in moist peat or soil so that the roots do not dry up while the planting is in progress.

Ferns always look best when grown as single crowns; when a mass of crowns has formed much of the beauty of the specimen is lost through the fronds intermingling. The opportunity should be taken when moving them to divide the clumps into separate crowns.

If the clump is a very large one, a start may be made by inserting two border forks back to back into the middle of the clump, avoiding pushing the tines through the centres of individual crowns. By gentle leverage the mass can be separated into smaller pieces, but the final divisions should be made with the aid of a sharp knife, for one has more control with the smaller instrument and less damage is caused.

After cutting away any dead rootstock and removing dead frond bases, the separated crowns should be planted in previously prepared ground with plenty of gritty leafmould worked in, when they should grow away and make good plants for another year.

Probably there will be left over quite a quantity of fern roots which, if shaken free of soil and washed, will make most useful fibre for making up orchid compost. Some friend might be very glad to have it if it is not wanted at home.

If there are more divisions than are wanted or can be accommodated, it is a good plan to present these to some gardening friend who may thereby be encouraged to take more interest in ferns and perhaps become a fern enthusiast. For it is often the case that once a gardener has tried one or two new ferns in his garden and has become aware of the vast field of interesting and beautiful plants which awaits his exploration, he becomes more and more enthusiastic and finds lasting satisfaction in acquiring and growing more and more varieties of hardy ferns. Once the interest is aroused, it seldom is lost.

Apart from the pleasure enjoyed in sharing one’s fern treasures with a friend, the more ferns are distributed amongst keen growers, the less likely they are to he lost. The rather startling statement that ‘the best way to keep a plant is to give it away’ I know to be well founded on the experiences of many growers, and the more the rarer varieties are propagated and distributed the more likely one is to get back plants which one may have lost.


Feeding Ferns

The feeding of ferns has been touched upon above, and this is best achieved by topdressing with sieved compost, leafmould or fibrous peat enriched with a light dressing of bonemeal, and well mixed with coarse grit. Anything in the nature of animal manure, unless a few years old, may do more harm than good. The object is to produce a sturdy plant full of health and of good colour, growing freely and able to resist adverse conditions and live to a ripe old age. Use of farmhouse manure may induce lush growth during the summer; it certainly will render the plants more susceptible to wind damage and winter loss, and shorten the plant’s life.

Artificial fertilizers are not necessary for a fern’s well-being, and provided that there are no actual mineral deficiencies in the soil they should not be used in the open air fern garden; the ferns will find all they require in the annual or biennial topdressing.

Before a topdressing is applied, any deep-rooted perennial weeds such as dandelions, docks and so on, should be eliminated, and I have found that the best way to get rid of these without disturbing the ferns is to dab the centre of each weed with a hormone weedkiller, using a paintbrush or wad of cotton-wool attached to a cane. The application is made in the early summer, taking care not to splash the ferns themselves. This procedure might seem to be somewhat tedious but it is effective, and, in fact, one can treat a great many weeds in this manner in the space of an hour.


Pests and Disease affecting Ferns

Fortunately ferns are seldom attacked by garden pests in the open, the chief enemies being slugs, snails, and woodlice which sometimes attack the young fronds in the spring. In fact, the only fern which I find to be constantly eaten by slugs is Asplenium fontanum, and this species is attacked at any time of the year. A regular scattering of slug-bait will keep down the slug population and is recommended as a regular fortnightly chore where a mixed border with other plants is concerned. This procedure should be started in early spring and go on until autumn, when once a month should be enough to maintain control.

D.D.T. powder is very effective against woodlice, if scattered around the plants in spring, taking care not to dust the fronds, as they are injured by contact with this compound. Woodlice seldom attack the mature fronds. They are a pest amongst sowings under glass, however, and (lusting around the containers is advised.

Birds can be a nuisance in early summer, as they scratch up the topsoil in search of insects and other food and may scratch up young plants, leaving them lying about on the surface. A watchful eye and immediate replanting seem preferable to covering the ferns with black thread or netting, as the nuisance usually ceases as soon as the young birds are able to look after themselves.

Where members of the primula family, cyclamen and dodecatheons are interplanted amongst the ferns, vine weevil grubs can cause havoc to these plants. Gammexane powder, or watering with colloidal gammexane, will control these pests, whose presence may not be realized until the primulas lift off at a touch, their roots having been eaten away.

Mountain Fern Thelypteris limbosperma Occasionally the stems of Lady Ferns, Athyriums and Polypodies are attacked by a kind of maggot which bores down the stems, leaving discoloured patches and causing the frond to collapse. I have never come across this pest, but I am told that removal of the fronds below the attacked places and burning them is an effective control.

Aphides seldom attack ferns, but sometimes they may infest the delicate unfurling fronds of Adiantums in spring. Dusting with nicotine or derris powder is effective and will not harm the fronds.

Sprays are not recommended, as although ferns appreciate humid conditions, artificial saturating of the foliage may be detrimental. Where there is a choice, leafmould is better than peat, especially for those ferns which do not prefer acid conditions, such as the Shield Ferns, Harts-tongues, and Spleenworts. Leafmould has apart form its humus-making properties, a small mineral content, whereas peat has practically no food value, and is valuable chiefly for its water-retaining properties.

Beech leafmould tends to be alkaline, which is an advantage for calcicole ferns; such ferns as Blechnum, Cryptogramma  —  the Parsley Fern, and the Mountain Fern Thelypteris limbosperma, which are calcifuge, are the ones which should have peat rather than leafmould.


08. May 2011 by Dave Pinkney
Categories: Ferns, Plants & Trees | Tags: , , | Comments Off on Looking After Established Ferns


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