Flower Garden Tasks in Late Spring


The herbaceous perennials will be growing fast and many of them will need supports. There are just as many that can be grown without staking, but the older, more popular perennials usually need some support. Amongst these latter are delphinium, erigeron, some euphorbias, lupin, peony, poppy, pyrethrum and Michaelmas daisies if growth is well enough advanced.

Bushy twigs like pea sticks, bamboo canes, stakes such as those which are used for dahlias and extending wire rings are some of the supports available, used in conjunction with fillis (soft string), plastic-covered wire, sweetpea rings or twist-ties. If put on when growth is about 30cm (12in) high and the stems attached so that the plants do not look bundled up and can grow naturally, the supports should be quickly masked by leaves.

Some of the lilies may also need staking; a single cane is sufficient for one plant. Chrysanthemums, dahlias and sweetpeas will already have been staked when planted or sown.

Indoor plants with growth which may be long enough to need support include achimenes, begonias, freesias from seed and climbers. The pendula begonias and some achimenes are natural trailers, very good for growing in hanging baskets. Most pot plants can be staked with split bamboo canes but there are special, extending, wire stakes for the double-flowered begonias; they finish in a kind of cup or half ring on which the flowers rest. Because their length can be manipulated, they can be used for a variety of begonias.

Sweetpeas will need frequent attention every three or four days, to remove tendrils, attach the stems to the supports and remove sideshoots.

Cutting back/deadheading

The remains of flowers should be removed from spring-flowering bulbs and herbaceous perennials. Rock plants such as aubrieta can be trimmed with shears and this treatment, far from being brutal, in fact clears out ‘dead wood’ to such an extent that some flower a second time, especially if encouraged with a little feeding after cutting.


Hippeastrums which have finished flowering and are now ripening their bulbs will be encouraged to flower next vear if given a liquid fertilizer with a higher potassium content than nitrogen and phosphorus. Potassium is the nutrient thought to be most related to the maturity of plants and it can, to some extent, make up for a lack of sun.

Other container-grown, spring-flowering bulbs, such as daffodils and hyacinths, can be treated in the same way until they die down; details of the frequency and quantity of fertilizer applications will be given by the manufacturer.


A layer of rotted organic matter about 1-2.5cm (1/3-1in) thick on the soil surface round such plants as annuals and herbaceous perennials, especially peonies and hellebores, will do much to prevent water being lost from the soil when the hot weather comes. If the soil is dry, do not put the mulch on, as it will simply do a good job of keeping the soil dry; wait until the rains come, or water heavily with the hose before mulching.


Sometime in late spring, the greenhouse should have shading applied to it, especially if it is a three-quarter span or lean-to against a south-facing wall. This is often chosen as an ideal situation for a greenhouse and certainly it protects from north winds and obtains the maximum effect from the sun’s heat. But it can get extremely hot and glaringly light, conditions in which only cacti are happy.

Shading is essential; hessian, chain laths, plastic sheet or Venetian blinds all provide temporary shading which can be made automatic, depending on the light conditions, or you can put a wash on the glass. An easily made, inexpensive one consists of a mixture of quicklime or fresh hydrated lime and sufficient water to give it the consistency of milk; adding a little size to the mixture helps it to stick. There are proprietary washes as well; one of these becomes transparent when rained on but remains opaque in sunny weather and also, unfortunately in dull, dry weather.


Weeding amongst small plants is vital if you want a good display of bedding and annual plants, from mid-summer until autumn. The biennials in the nursery bed should be carefully watched, too, and perennial weeds in borders amongst herbaceous perennials should be systematically eradicated while still tiny, otherwise you will never be rid of such unwelcome plants as ground-elder, bindweed and oxalis. The hoe and the handfork are great allies for cultivated ground; paths, drives, paved terraces, patios, garage aprons and steps can be kept clear with chemical weedkillers.

Compost-heap making

The material for this will mainly be lawn-mowings, which are excellent as they heat up quickly, weeds, and cut-back spring-flowering plants. There may also be some excess plant growth in the pool, which will need clearing out, and there are bound to be leaves, which seem to come down whatever the time of the year. As you make the heap, alternate layers of vegetative material with activator or sulphate of ammonia or, better still, with a thin layer of animal manure.


Unless the weather is unseasonably hot, watering will be confined to the greenhouse plants and will be a daily necessity. Water which is at the same temperature as the atmosphere is best, so there should be a tank containing it in the greenhouse. A galvanized iron one, covered so that light is completely excluded, will ensure that the water remains clean and free from algae, dirt, insects, disease and even small mammals. A water-butt outdoors to collect drainpipe overflows should also be covered, but it is difficult to keep the water clean in these. A strainer on the end of the pipe will help but may result in flooding unless cleared out regularly. Butts made of polythene or plastic tend to encourage the growth of algae internally. The same is true of watering-cans; galvanized or painted ones are best.


Roof ventilators in the greenhouse can be left open permanently; side ventilators can often be opened during the day and on really hot days doors can be left open. The temperature can also be lowered by damping down, that is, sprinkling the floor, staging, walls and plants with water two or three times a day.

Frames must be ventilated, too; this is very important, as they will contain various young plants which will be wanted for planting out at the end of late spring or early summer. On warm, sunny days, the lights can be pushed back completely and as the night temperature rises, they can be propped open at night, gradually being lifted more and more until they are left off altogether, unless the temperature is still dropping below 10°C (50°F) at night.

Treating pests and diseases

Greenfly and caterpillars will be the main problems but another pest which will become an unseen nuisance from now on is the capsid. This is a green insect which feeds by sucking the sap from young leaves and shoot tips and from flower buds, with the result that the flowers, if they develop at all, are misshapen, lopsided and stunted. Dahlias and chrysanthemums are particularly vulnerable.

Capsids are about ten times larger than greenfly and quick-moving; they drop to the ground when disturbed, so are often missed. Damaged leaves will have pin-prick holes to start with, but rapidly become tattered and new shoot growth stops. This is one case when precautionary spraying is advisable, before damage or pests are seen, at the beginning of late spring and again as the manufacturers advise.

Another unseen pest which can do a lot of damage to narcissus bulbs is the narcissus bulb fly. The adults lay eggs in the soil close to the bulb’s neck and the maggots which hatch bore into the bulb and feed in the centre for about two months from early summer onwards. Even if the bulbs do not die at once, the following year they will produce only a few short leaves. Dusting the soil round bulbs with an insecticide in the middle of late spring helps and should be repeated twice more at about two-week intervals.

Slugs and snails will need trapping or otherwise treating and there may be some grey mould in the greenhouse, which can be dealt with satisfactorily by hand removal.

more on Late Spring Jobs in the Flower Garden …

29. August 2011 by admin
Categories: Flower Garden, Types of Gardens | Tags: , | Comments Off on Flower Garden Tasks in Late Spring


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