GARDENING

Press, 25 May 1984, Page 10

GARDENING

by

M.Lusty

I am enclosing this flower and leaf from a plant which has been growing in my garden for the past eight years. It appears to be quite rare as I have yet to find anyone who knows it. It flowers through spring, summer and autumn.— V.B. (Teviot, R.D. 2, Central Otago.)

The plant is Lychnis coronaria, a hardy, long-flowering perennial which could not be classed as “rare.” Apart from its propensity to flower for such a long time, this plant also has virtue in its silver-grey foliage. It can be increased by means of seed, or the division of existing plants during the winter.

As a new grower of amaryllis some of the advice given has differed very considerably, consequently I would like to know the correct cultivation necessary. (1) Pots have been kept moist after flowering, with an occasional liquid feed given — how often should this be done? (2) Where should the pots be placed after flowering? (3) Can the plants be kept in a glasshouse, and if so do they need to be placed in the ground? (4) When do you stop watering? (5) Can they be repotted each year with a potting mix? (6) If they are not repotted, should liquid feed be given in the spring? (7) Do amaryllis normally flower each year?—B.W. (Westport.) Many seasoned growers in plants have their own little methods of how they tend their plants. However, there are some basic applications which are generally followed in most cases. (1) Regular feeding and watering can be maintained until early autumn when the leaves show signs of yellowing. The bulb should be allowed to dry off completely until restarting growth. At this stage the withered foliage should be completely removed and the Sts kept in a cool dry place. Pots can be kept in the glasshouse and it is not necessary to bury the pots. (5) These bulbs do not like root disturbance and are best left for three to four years provided some of the top soil is replaced with quality potting mix. (6) Liquid feeding can be on a regular weekly basis once growth commences. Watering should also be regulated, gradually increasing the amount as growth develops until the flower bud shows at which stage the soil should be just moist. (7) Insufficient light is considered to be the major factor towards inhibiting

flowering so make sure that the plant is exposed to maximum light from the commencement of growth until the leaves fade. Finally, it may be worth noting that the correct name for these bulbs, which can develop to considerable size, is Hippeastrum.

Please would you be kind enough to identify the following: (a) The enclosed persistent, hair-like weed? (b) The enclosed catkins from pines which were recently sending out clouds of pollen. I thought this was a springtime thing, (c) My long-estalisbed dwarf rhododendron, Elizabeth, is showing a few yellow leaves. I have given it some Alaska, (d) My long-established Lapageria is not as robust as it used to be. It has fewer flowers and leaves, (e) What is the white thickening of some leaves on

Azalea Indica? Years ago I was advised to pick them off and burn them as they appeared. I have done this but still they persist and have spread to a nearby new one.— D.M. (Christchurch.)

(a) Hydrocotyle species, (b) Unseasonal flowering does occur quite commonly in many plants, but seems to be a little more widespread this year, (c) Leaves of the affected rhododendron were not included so it is not possible to know whether the symptoms of yellowing mentioned are possibly due to iron deficiency or the need for general feeding. An application of proprietary acid fertiliser mixture may be best but do not expect instantaneous results — it takes several months for a nutritional shortage to be overcome, (d) Lapagerias prefer a cool, moist root

run well endowed with organic matter such as leaf mould and fibrous peat and require a slightly acid medium with a little shelter to do well, (e) The azalea is suffering from the fungal infection known as azalea gall. The diseased leaves should be destroyed and several sprayings of a copper based material should be applied, particularly in the spring time. This disease can be persistent if not dealt with.

My eight-year-old rhododendron is shedding leaves very heavily this year as opposed to a light fall in previous years. Can you, from the enclosed leaves, give me a reason for this and should the bush be treated in some way? Also, is it all right to prune a rhododendron, and when should this be done? — A.M. (Christchurch.)

Rhododendron are respon-

sive to pruning, although there is some variability to the rate of recovery from this treatment. The best time is generally as soon after flowering as possible. Obviously, there is something amiss if the plant has been shedding leaves in the way you describe. It is possibe that the ground is too dry — maybe it is too porous — and in consequence the plant is struggling to survive. Dryness can affect nutrient uptake as well. Check on this aspect, even lift the plant to inspect the root system for growth and consider an alternative site or improved cultural methods. Gardeners’ Queries should be sent directly to Mr Mike Lusty, 56 Wayside Avenue, Christchurch. Place well wrapped samples separately in plastic bags with air holes. Provide representative, goodsized samples, your name, and a nom-de-plume for publication,