HYDRANGEAS IN POTS

New Zealand Herald, Volume LXXII, Issue 22000, 5 January 1935, Page 8 (Supplement)

HYDRANGEAS IN POTS

CONTROLLING THE COLOUR

When searching for a plant that will give a tremendous amount of bloom and romain at its best over a long period, hydrangeas should not be overlooked. It is not a difficult plant to grow, nor is it in any sense delicate, so for the cool greenhouse or verandah it can be counted as one of the best of summer subjects. Luckily it is always possiblo to purchase good plants in pots at this time of year, and the buyer will be able to obtain the full benefit this season, and also be able to select the colours most pleasing to the individual taste.

Colour is very unstable, and the nurseryman is frequently blamed for supplying the wrong one, when it is the purchaser's own soil that is to blame. Loam containing lime can be used for the pink and white-flowered varieties, but for blue-flowered hydrangeas soil containing lime must not be used. If that is not available, only peat and leafsoil should be used with plenty of gharp sand. Only hydrangeas _ which naturally have pink flowers will bear blue ones in districts where iron is abundant in the soil, or when treated with stances designed to make tho flowers change colour. White-flowered hydrangeas will only change to a starchy white or slate colour. The deeper pink the flower is normally the more intense will be the blue following the use of a blueing powder. The simplest method of treatment is to purchase one of tho rhemical blueing powders sold by horticultural seedsmen, and mixing this with the soil when potting and dissolving it in water, and using it when tho flower buds show.

One pound of blueing powder should be added to every bushel of lime-free soil. To intensify the colour, plants

inserted in a 4in. pot. should be watered once a week with 2oz. of blueiDg powder, dissolved in one gallon of water. The powder is best dissolved in a little hot water first. Liquid manure and blueing powder are used in alternate weeks. Other means of obtaining blue hydrangeas include mixing iron filings with,the soil at potting time, watering with alum at the rate of one teaspoonful dissolved in a gallon of rain water, or three ounces of aluminum sulphate dissolved in one gallon of water. These, however, are not so certain in results as the blueing powder. Some gardeners like to grow their own plants from cuttings to flowering. Tho next two months are the best for inserting tho cuttings. These should be taken from tho ends of nonilowering shoots; each should have two or three pairs of leaves. The cuttings are made in the usual way by trimming off the bottom leaves and cutting square below a joint. Tho cuttings may be inserted, two or three round the Bides of a four-inch pot. If kept moist and shaded they will soon mako roots; as soon as sufficiently rooted, they are transferred to single pots of three-inch size, where they may stay for the winter. In early spring the plants ore potted on, tho strongest into six-inch and the weaker into five-inch pots, which are quite large enough for the first season. In early spring the plants will grow with great rapidity, and when the pots are full of roots doses of weak liquid manure may bo given. Plants of this size the first season will carry one huge terminal bloom. In tho succeeding seasons the plants may be grown on to a large size, with a large number of magnificent blooms, but it is tho usual practice to raise a few fresh ones every year, and dispose of large ones in the borders and shrubberies to use for cutting.