Gardeners' queries Tree peony has botrytis

Press, 9 December 1983, Page 15

Gardeners' queries Tree peony has botrytis

GARDENING

by

M.Lusty

Could you please tell me what is wrong with my tree peony? The most exposed part of the plant became affected first. I missed pruning the plant last winter. Should it be pruned back harder this year? L.J. (Chch).

This peony showed the symptoms of botrytis or what is commonly called grey mould. Infected shoots or similarly unhealthy buds should be removed and the diseased growths should be destroyed. Spray the plant with benomyl, or a copper based material. Infection could be due to various factors, including over feeding, too late in spring, too deep planting, and or mulching, and excessively wet conditions.

I grow lots of daffodils in my lawn but I think that they have become too closely knit as about a third of them failed to bloom. I intend to dig up a proportion each year and replant. When should this be done and would it be possible to replant in order to have a succession of flowering, as at present they all bloom at once? G.W. (Kumara). It is not possible to account for the failure of your daffodils to bloom without knowing more about conditions etc. Replanting should be done as soon as the foliage begins to fade. Successional bloomng is possible by means of temperature control but this would only provide variation in the flowering for one season. Variation in the flowering period could be better obtained through species and varietal selection.

I have a front lawn laid about 20 months ago. The enclosed sample of weed is increasing with great rapidity. Would you kindly identify the weed and

advise what can be used to eradicate it, Banvine having failed to do so? When is the best time to spray it? P.R. (Chch). The plant was a little too dessicated to revive for full recognition but it appeared to be birdsfoot trefoil, Lotus corniculatus. Banvine can be effective against this plant but the combination of MCPA and MCPB is much to be preferred. This preparation should be applied as a fine spray together with a wetting agent. There is still time to apply the spray now before the onset of summer, otherwise it would pay to wait until autumn.

I enjoy beef in any way of cooking but even more so when accompanied by a good helping of horseradish sauce. I would like to grow it although it was suggested to me that it is a weed 1 would not want in my garden. Where can I get it and perhaps you could also tell me how to make the sauce? “Roast beef”. (Chch).

Horseradish is available from various garden nurseries and also from specialist growers of herbs. It is most certainly regarded as a weed by many people as it will spread if given the chance. Horseradish sauce is obtainable from food stores and it is also possible to purchase horse radish powder with which to make the sauce. Recipe: To every

30g of horse radish add 1 dessertspoon of mustard, 3 dessertspoons of both sugar and malt vinegar, 4 tablespoons of whipped cream, and a little pepper and salt; mex well.

Please could you tell me how to get rid of this rust which for the last few years has ruined our lettuces. Until now these grown in the glasshouse were good. We use a lot of home-made compost. C.J. (Chch).

The disease afflicting this lettuce is ring spot, sometimes called “rust”. Once established, the disease can spread readily under conditions favouring infection —

low warmth, humidity and moisture, especially where planting is close. Badly diseased plants should not be used for compost or left lying around. Crop rotation is strongly recommended as is dusting with a fungicide, such as captan, in preference to spraying. The fungicide should be diluted with talc, (1 part fungicide to 7 parts talc) well mixed before applying.

I have had a lovely large amaryllis flowering in a pot indoors which I would like to retain as such. Now that it has finished flowering I have cut the flowering stems out and all that is left are the leaves. What do I do with it now? M.S. (Chch).

The plant referred to is correctly known as Hippeastrum, although popularly called amaryllis. Once flowering is over, the flower stem should be cut off about 20 to 25mm above the neck of the bulb. The leaves should be left and removed only when they wither. After flowering leave the plant in a position of full susn and gradually reduce the amount of watering to nil to enable the bulb to dry off and have a rest period. These bulbs resent root disturbance and should be repotted only every third or fourth year. A really good potting mix should be used, the repotting being carried out about late September/ early October. Thereafter apply plenty of water.