Having traveled the long way from America to Europe several centuries ago, dahlia has managed to adapt to the most diverse climatic conditions. Today this flower is loved and grown in different parts of the world. What is the secret of such popularity? Dahlias are beautiful, ornate, diverse and unpretentious in care.
Just know a couple of simple tricks to make dahlias a signature feature of your flowerbed or garden!
- Should I buy tubers with tall sprouts?
- Is it true that dahlias are not afraid of acidified soil, but the soil should definitely be given a rest from this plant?
- Why can’t dahlias and asters be planted next to each other?
A lot of small or a couple of gorgeous flowers on a bush – you can decide! Do you love dahlias, but there is no possibility to bother with the annual digging-out and planting or organize storage? There is a solution! We tell you…
Dahlia planting and care
- Planting: from the second half of May to the second half of June.
- Dug out: in autumn, after the first frosts.
- Storage: at 3-5 ˚C and 60-70 % humidity.
- Flowering in summer and fall.
- Lighting: bright sunlight.
- Soil: Anysoil, but fat garden loam of weakly acidic or neutral reaction is preferable.
- Watering: Plenty of water, 1-2 times a week.
- Feeding: organic and mineral every two weeks alternately.
- Gartering, pruning, palming: obligatory for high-growing varieties.
- Propagation: by seeds, tubers.
- Pests: slugs, earwigs, salivary worms, flower beetles, aphids.
- Diseases: powdery mildew, bacterial cancer, overgrowth, smut, gray rot and viral mosaic.
Dahlia are one of the most beautiful and longest flowering garden flowers, with a wide range of colors and shapes. They bloom from July until frost, and this is the most important advantage of dahlias, besides their beauty. The first dahlia tubers were brought to Europe from Mexico at the end of the 18th century. The dahlia received its name in 1803 from botanist Carl Wildenau, who named the plant after the famous botanist, ethnographer and geographer from St. Petersburg, Academician Johann Georgi. There are about thirty species and about 15,000 varieties of dahlia.
The shapes, colors and varieties of dahlia are so diverse that they can be used to decorate not only beds but also borders and as solo, even potted, plants. Dahlias are dazzlingly beautiful, yet completely unpretentious. The main thing that is required for their successful growth and lush flowering is to choose the right place of planting, provide the necessary soil composition, timely watering and fertilizing.
The seedlings should be bought not earlier than mid-spring, and the tubers should be fleshy and strong, with already visible, but not tall sprouts. Soft or dry tuber is better not to take.
How to Grow Dahlias
Growing dahlias involves labor-intensive digging and responsible storage of the tubers, but if you’re intimidated by this hassle, you can grow annual dahlias from seed. Annual dahlias are as beautiful and unpretentious in culture as perennials and the selection is quite wide: Coltness Hybrids up to 50 cm high with abundant unflowered flowers in various colors; bronze-leaved Redskin; small macerated Rigoletto; early Figaro … You can buy the seeds and sow them in the open ground in the middle of May, but then they will bloom only by the middle of August. If you want them to bloom earlier you have to germinate the seeds.
In early April you will need to sow dahlia seeds in greenhouses or plastic containers using calcined sand as soil: Pour the seeds on a layer of sand, add sand on top, moisten well and cover with clear plastic. Germinate the seeds for about ten days at a temperature of 25-27 ° C, then sprouts need to be pickled in separate pots. The soil mixture should be moist and friable, it can be bought or prepared: one part peat and sand and two parts leaf soil. Three days before picking the soil should be treated with a hot solution of manganese (70 °) dark pink. After picking, the seedlings are watered as the soil dries up. In mid-May it can be planted in the ground.
Where to plant
The preparation should begin with the choice of a planting place. Dahlia flower cannot tolerate draughts, but requires a well-ventilated and illuminated place, so plant dahlias in a sunny area, protected from the wind. The soil on the site should be well-drained, water-permeable and nutritious. Dahlias can grow in soil with a lack or excess of acidity, but a slightly acidic or neutral environment is optimal for them. If the soil on the site is too acidic (pH 5-4), add burnt lime, but if the pH is more than 8.5, you can acidify the soil with peat.
In the fall, when digging, enrich the allotted plot for dahlias with humus and compost (3-5 kg per 1 m3). In the spring, before planting, spread mature compost (not deciduous) and some wood ash over the plot again and rake it up. To rid the dahlias of disease and keep them from degenerating, it is advisable to change the planting site every year, letting the soil rest from the dahlias for at least three years. Do not plant dahlias where asters or plants prone to fungal diseases grew before them.
Preparing the tubers for planting
In April, dahlia roots (tubers) should be prepared for planting: clean them from dry roots, remove damaged places, treating all cuts with greenish. Then plant the tubers in a container with nutritious soil or peat so that the dahlia tubers act 2-3 cm above the surface, and keep them for two weeks at a temperature not below 18 ° C in good light. As soon as the buds appear, cut the tubers into pieces so that each has a bud with a root neck. Sometimes one tuber yields five such pieces. The split tubers should be allowed to germinate in a box for a while longer, and then planted in the soil by removing the side shoots that have reached a height of 10 cm. Cut shoots can be used as cuttings: planted in the soil, placed in a dark place and well watered. Nurtured cuttings are planted in a permanent place. Splitting tubers and cuttings are made to increase the amount of planting material and prevent the degeneration of the plant. If you don’t have such a need, you don’t have to divide the tubers.
Planting dahlias outdoors
Dahlias can be planted in the ground when the soil has warmed up, usually in late May or early July. Pits under dahlias should be three times larger than the clump of roots (40x40x40), so that the dahlia roots were immersed in them completely and left another 5-7 cm. At the bottom of the hole, lay a layer of decomposed compost or manure, then cover the manure with earth, so as not to burn the dahlia roots, place the sprouted tuber and bury it so that under the ground there were a few centimeters of the stem. If you have chosen a variety of tall dahlias, install and fix a support for the future stem at once. After planting, abundantly water the seedlings with cold water, and mulch the soil around them with a five-inch layer of fine wood bark or sawdust, previously mixed with peat or compost.
Care of Dahlias
How to care for dahlias
Mulching the site with dahlias, in addition to protecting the plants from slugs, will give you the opportunity to abandon such tedious work as weeding and loosening the soil, and also will not allow the soil in hot days to dry out quickly. Water dahlias abundantly 1-2 times a week (if it is not raining), but do not let the moisture stagnate in the roots: dahlia tubers are prone to rotting. In extreme heat, it helps to retain moisture by ducking after watering. Before the next watering, rake away the soil from the stems, water the plants, and then dip them again.
During growth, dahlias should be fertilized every two weeks, alternating mineral fertilizers with organic: ammonium nitrate (15 g per 1 m3), tincture of cow manure 1:10 or poultry manure 1:20. With the appearance of the first buds begin to make superphosphate and potash fertilizer at the rate of 30 g per bucket of water (enough for 8 bushes).
Support for dahlias
Since dahlias have a hollow stem, and a strong wind or rain can break it, it is necessary to tie dahlias to a support peg. If the stem does break, try to splint it by attaching a sturdy branch to the stem, fastening it and supporting it to prevent it from tilting. Timely and careful care of dahlias can save even a broken shoot, which will reward your care with beautiful blooms.
If you are interested in the quality of inflorescences rather than the quantity, do not leave more than three shoots in the bush, otherwise the inflorescences will be smaller in size and not as decorative. You should leave 1-2 buds on each flower stalk. Remove the buds that have blossomed so that they do not delay the formation and growth of new ones. Throughout the season, try to remove the lower side shoots of the tall dahlia varieties, these shoots can then be used as cuttings. In low-growing (pom-pom, cactus) and single dahlia bushes, the side shoots may not be removed.
Young juicy dahlia stems attract slugs and buds attract earwigs, so treat bushes in the evening with wormwood or celandine decoctions about once a week if you see the first signs of pest aggression. In hot weather, spray dahlias with systemic insecticides against thrips, aphids, mites and caterpillars. Aphids love dahlia pests the most. Try the old-fashioned, tried-and-true way to combat it: spraying the plants with a soapy solution.
Harvesting dahlia tubers
After the first frost, dahlia tubers should be dug up, cut off the remaining foliage and pagons, leaving only five to ten centimeters of the stem. Some gardeners cut the stems and leaves a few days before digging up the tubers, but if any moisture gets on the cut part, the base of the stem may rot, so cover the dahlias immediately with aluminium foil after cutting the stems. The tuber neck is particularly brittle, so start digging up the tubers in the morning, in dry weather, so that they have time to air-dry and become less “brittle”. Also, dried tubers are easier to remove soil residue from.
Digging out the tubers
Dig around four sides of the plant about 30 cm from the stem to cut the long conducting roots, bring the forks under the root ball and push it out of the ground. Carefully peel the clods of earth from the tubers and turn them over to dry. When you have dug up all the tubers, rinse them with a garden hose from soil that contains disease-carrying microorganisms. Do not delay with harvesting the tubers because after the first frost, it may get warmer and the buds sleeping in the tubers may wake up and start sprouting, which is detrimental to the plants at this time.
How to store dahlias in winter
Correctly storing dahlias in the winter is 90% of your growing success. The tubers should not be left to dry out too dry over the winter because they will give weak sprouts in spring. Under-drying will cause the roots to rot during storage. If any mechanical damage is found on the tubers, they should be trimmed and then covered with charcoal. Root necks, so that they do not rot during storage, powder them with ash or chalk.
Dahlia tubers are best stored at 3-5°C and 60-70% humidity in a well ventilated room. A dry cellar is suitable, but storing vegetables nearby can create more humidity, increasing the risk of rot and fungal growth in the tubers. You can put the tubers in a box on a layer of dry peat and cover them with peat, or you can use sawdust of coniferous species or sand instead of peat. If the tubers suddenly start to dry out or wilt, the insulating material is slightly moistened. If there is no ventilation in the basement, you will have to turn on the fan three times a week for half an hour.
If you do not have a basement or cellar and have to store dahlia tubers in your apartment, place the boxes with the tubers in the coolest place (next to the balcony). You can put the tubers in plastic bags with insulating material (sawdust, sand, dry peat) and tie them tightly. Some flower growers, wrapping each tuber in newspaper, put them in a polyethylene bag, which is placed in a cardboard box and placed in a cool place, such as a glazed loggia. Only in this case, you will have to keep an eye on the temperature outside all the time, so that a sudden cold snap or frost will not kill your planting material.
The least suitable places to store dahlia tubers are warm and humid places, but you can preserve them even in such unsuitable conditions if you cover the tubers with paraffin. Melt paraffin in a water bath, immerse the tuber in it for a second, let the film harden for a few seconds and then dip the tuber back into the liquid paraffin. After the waxing procedure, place the tubers together with dry peat, sand or sawdust in a cellophane bag and tie it tightly. Before planting, these tubers will need to be lightly rubbed to allow the film to crack.
During the winter, do not forget to inspect the tubers to be able to eliminate the probable appearance of rot in time. The affected areas should be cleaned to healthy tissue and treated with hardwood charcoal powder or green.
Types and varieties of dahlias
Dahlias are classified according to the shape and structure of the inflorescence, in modern culture there are 12 major classes of dahlias, but as new varieties appear, new classes also appear.
So, the most popular dahlia varieties:
Dahlias, which have a single row of flowers, reaching a diameter of 10 cm and a height of 45 cm to 60 cm. Simple dahlias include yellow Yellow Hammer, pink Princess Marie Jose, reddish-orange Orangeade
From one or more rows of marginal flowers, with elongated tubular flowers in the middle. Inflorescences reach a diameter of 10 cm and a height of 60 to 90 cm. The most popular varieties are Vera Higgins bronze, Lucy yellow and purple, Comet red.
Dahlias are the same size, but taller – from 75 cm to 120 cm. They have one marginal outer row of flowers, on top of which is a row of shorter and curled flowers of a different color, looking like a collar: Chimborazo (red with cream), La Gioconda (scarlet with gold), Claire de Luna (yellow with cream).
Dahlias are slightly larger, from 12 cm to 15 cm, with two or more flat marginal flowers and tubular flowers in the center. They reach the same size in height as the collared ones. Fascination mauve and Symphonia crimson red dahlia are popular.
These include the mauve giant Jocondo, the large yellow Thames Valley, and the miniature orange David Howard. All varieties have terry inflorescences from 8 to 25 cm in diameter and up to 60 cm in height.
Dahlias are spherical, sometimes slightly flattened, 8 to 15 cm wide and 90 to 120 cm high: Doreen Hayes red, Esmonde yellow and Crichton Honey peach red.
The ball-shaped, terry florets are 5 centimeters or more in diameter. The marginal flowers are curled, with a blunt or rounded tip. It reaches a height of 90 to 120 cm, the pink Noreen, Hallmark in lavender and pale Willo’s Violet.
Dahlias have terry-shaped inflorescences 8 to 25 cm in diameter or more, reaching a height of 90 to 150 cm. The marginal flowers are curled, narrow and pointed: giant pink Danny, miniature yellow Pirouette, large red Visit, small red Doris Day.
Terry inflorescences are 8-25 cm in diameter, 90-150 cm high, with marginal flowers curled from the middle to the ends: large yellow Nantenan, tiny yellow Yellow Mood, medium-sized orange Autumn Fire and small white White Swallow.
Water lily-like, terry, beautifully regular shaped, 7-20 cm in diameter, 70-130 cm high: Brushstrokes purple, Gerri Hawk delicate pink, Genette white.
Types of dahlias that are unlike any of the other varieties listed.
In addition to the variety of forms, dahlias also differ in a variety of colors, and there is even a black dahlia, or rather, red-black, appeared due to the accumulation in the plant a large number of pigments anthocyanins. But the ultimate dream of all breeders is to breed blue dahlia, and although their efforts have not yet been successful, the hope to one day see this miracle is so strong that it has resonated with writers and filmmakers.
- Read about the topic on Wikipedia
- Features and other plants of the Aster family
- List of all species on The Plant List
- More information at World Flora Online