Cultivation of dahlias in s.a.

Dahlias will thrive in any kind of soil providing some preparations are undertaken. If possible, the site chosen for planting should be sunny, well drained and sheltered from strong winds. Drainage in heavy soils can be improved by raising the beds with topsoil or by adding generous quantities of coarse sand. Poor soils can be improved by the addition of well decomposed compost and organic manures.

Planting time – Tubers are planted out when the danger of frost is over. Early planting’s, made in spring, will provide you with flowers over the summer months, whilst tubers planted in November / December will result in brighter, better formed blooms in the cooler months of autumn.

soil preparation – At least two weeks before planting work the soil over to a fine tilth, incorporating a good dressing of fertiliser at the same time. Organic, pelletised fertiliser mixed with a complete fertiliser would be a good starting blend. Water the soil a few days before planting.

Planting – If you are using stakes to support your plants ensure they are placed in the ground before planting commences. Giant varieties should be planted about 90cm apart, with others about 60cm apart. Tubers are planted horizontally with the growing shoot facing upwards and about 25mm from the stake. See Diagram 1.

Plant them to a depth of between 100mm to 150mm, water lightly to settle the soil. Except in very dry conditions they do not require much watering until the plant emerges from out of the ground.

Irrigation – Ensure that the plants never lack water and a thorough watering once a week is not too often in some locations.

A fine spray sprinkler set to water overhead until flowers appear, then set lower to water the foliage is best. Make sure that the water penetrates deep into the soil.

Light sandy soils will need more frequent watering, whilst heavy clay soils will need less.

Weeds – Cultivate to keep the weeds in check until the plants are well advanced, mulch applied around the bushes will then control weeds and also provide a cool moist environment in the summer months.

Stopping and pruning – Pinch out the growing tips when the plants are about 150mm to 200mm high, this will encourage lateral growths and produce a much bushier plant. Tie the plant with soft twine, and as the plant grows upwards and outwards, keep placing ties around it to support and protect from winds.

If you want larger blooms with longer stems, some of the side buds can be removed from around the main central flower on each stem, leaving just the one flower to develop.

See diagram 2.

General care – A regular application of a liquid fertiliser is beneficial to the production of healthy blooms. One low in Nitrogen is preferred. Be sure to remove any spent blooms from the bushes to ensure continual flowering.

Pests and diseases – Dahlias are subject to the usual garden pests, thrips, aphids, caterpillars etc are present in the garden and will attack the plants. You can control most pests by maintaining control of weeds and overhead watering. The most common disease encountered will be powdery mildew; this can be controlled with sulphur dust.

Digging and storing – When the plants have finished flowering, cut down to just above ground level, removing all the ties from the stakes as you go. If you intend digging up the clumps use caution when lifting them by supporting the tubers, as any with broken necks will not grow again. Store the clumps, with the soil still on them, under an evergreen shrub, covering them with straw or wood shavings. Spread snail bait to protect the young shoots. Don’t forget to tie on a label with the name or colour of the variety.

Alternatively, the clumps can be washed off when lifted and the tubers carefully cut from the main stem, making sure that you have part of the stem attached to it.See Diagram 3.

Store the cut tubers in foam boxes, packing them with slightly damp, coarse sand or sawdust. Place the boxes in a cool place in the shed until spring.

Frequently asked questions

‘Q’Can I leave my clumps in the ground?

‘A’Yes, provided your beds are raised enough to prevent waterlogging in winter. The tubers will rot if allowed to remain in a waterlogged bed. If you have a sandy, free draining soil they can stay, but will lose their vigour in time. The main principles in digging them out each year is to rest the soil and give you a chance to rebuild the nutrient levels, thereby ensuring plenty of healthy blooms next year.

‘Q’What do I do when I have a long shoot on my tuber before planting?

‘A’Don’t cut the shoot off until a week before planting, as you will deplete the reserves in the tuber. If the shoot is very long, it is of no use, but if you have a nice healthy shoot about 75mm long, cut it off cleanly with a razor blade leaving about 5 to 10mm on the tuber, place the cutting in a small pot of 75% sand, 25% peat and put in a warm, humid spot. It will form roots in about 2 to 3 weeks and grow into a small plant. When large enough, plant out in the garden

Q’When should I pick the blooms?

‘A’The ideal time is in the early morning, before the sun reaches them, or in the cool of the evening.

‘Q’How can I make the blooms last longer?

‘A’Pick them as above, then place them in a deep bucket of water until ready for arranging. If possible use rainwater or add flower preservative to your vase water. Change the water regularly and trim off any blackened ends of the stem.

‘Q’Why won’t my tubers shoot?

‘A’If the neck of the tuber is broken, it will not shoot. The tuber needs part of the stem attached, as well as the main body, for it to grow, not all tubers carry ‘eyes’ necessary for growth.

‘Q’My plants have not come up after three weeks in the ground?

‘A’Your tuber may have rotted. Scrape away the soil along side where it should be and carefully expose the tuber, you will see if there is any sign of life. If so, cover over and leave alone.

“Q”Is it necessary to divide my clump before planting?

“A”If your clump consists of two or three tubers it can be planted whole, if there are too many more cut off any broken or damaged ones, divide into smaller clumps and then plant them, provided there are eyes on each clump.

Recommended varieties to grow

These would be available either from members, at the annual tuber auction in November or the Society’s stand at the Royal Show.

Large sizes

Como PollyLavenderDecorative

KaringalLemonDecorative

Aitara MajestyYellowCactus

Forby FrostWhiteDecorative

Hamari AccordLemonCactus

Susan FrenchSalmon PinkCactus

Winkie ColonelRedDecorative

Bracken SarahBronzeDecorative

Smaller Sizes

Karras 150WhiteCactus

NationwideAutumn TonesDecorative

EmbraceLight BronzeCactus

Night LifeRed / Gold TipsCactus

Araluen FireOrangeCactus

Bracken JoanMauveDecorative

Formby AlpineWhiteDecorative

Other types

FigurineShell PinkWaterlily

L’ancresseWhiteBall

CornelRedBall

Christie StarletMauve & WhiteOrchid

Kens GalaMauve & WhiteCollerette

Golf BallBronzePompon

Aitara PicardyPink & WhiteFimbriated

Society members use and

Recommend the following products:

“earthcare 2000”

“seasol”

(Seaweed extract products)

and

“neutrog”

(Organic Fertilisers)

TheDahlia Societyof SA Inc

Application for Membership Form

I / We hereby apply for membership of The Dahlia Society of SA Inc.

Enclosed is $ ______being my / our subscription for the current year.

Name

(Block Letters Please)

Address

Post CodePhone

Date

Signature

Proposed By

Seconded

 Endorsed by Society Members on receipt of application.