Another old-fashioned plant, which is very fashionable at the moment, and is a stalwart of country shows. Growing dahlias can also be quite addictive!!!
I remember visiting two elderly spinsters in their 80s, who lived with their brothers on their family property, just north of Guyra, New South Wales. The ‘boys’ had extensively cleared the farm of every little single tree, so much so that the paddocks looked like a dry crater on the moon! One of the sisters did all the cooking for the family, as well as feeding the chooks, bottle-feeding all the abandoned lambs, and caring for injured animals rescued by WIRES. We were treated to a magnificent afternoon tea of three different types of cakes, as well as freshly-baked scones and cream, biscuits and lamingtons, which we ate in the dark, poky kitchen with a joey in a sling on the back of a nearby chair. Apparently, this spread was standard fare for the boys, hungry after a morning’s work on the farm. She also cooked meals for the brother in town, whose wife had left him, and one of the ‘boys’ would drive the meals the half hour to town every afternoon. The only time this wonderful old lady ever left the property was Show Day, when they would all go to town to see how her sister’s dahlias had fared. The gardening ‘outdoor’ sister not only grew the family vegetables, but also had the most wondrous collection of dahlias of every type and colour in a neat patch next to the bedlam of the chook yard, full of random, makeshift wire enclosures for the poultry. It was an amazing sight!
Another wonderful place to see dahlias in all their glory is ‘Country Dahlias’ in Winchelsea, Victoria, as seen in the photos above and below. For their catalogue, see : http://www.countrydahlias.com.au/. Jenny Parish has over 20,000 Dahlia plants of 2350 varieties. You can visit the farm from 1st March to 22nd April each year, as we did in March 2013. ($7 per adult; closed Fridays). There are display beds out the front, trial beds out the back and paddocks full of dahlias of every conceivable form and colour – a spectacular sight indeed! Dahlias can also be bought from Tesselaars (see post on Favorite Nurseries : https://candeloblooms.com/2016/03/08/favourite-gardens-regularly-open-to-the-public-nursery-gardens-in-victoria/). Tesselaar’s website is : https://www.tesselaar.net.au/ . Other bulb nurseries nearby include: Club Creek Bulb Farm (https://www.facebook.com/clubcreekbulbfarm/) and Drewitt’s Bulbs (http://www.drewittsbulbs.com.au/). Local shows are also a great place to see the dahlias growing in your area and if you become really hooked, the Dahlia Society of Australia (www.dahliasaustralia.org.au) can direct you to the Dahlia club in your area , as well as alert you to the upcoming Dahlia conferences and tuber auctions. These photos are from the 2015 Bega Show. Dahlias can be found in many historic or old gardens like Rippon Lea, seen below. For more on the latter, see my post : https://candeloblooms.com/2016/02/09/favourite-gardens-regularly-open-to-the-public-historic-homes-and-gardens/
I was not surprised to discover that there was a Portland Dahlia Society, as there is a wonderful display garden of some very old varieties in the Portland Botanic Garden, seen in the photo below. Some of the varieties were as old as 1857! See my post on Late 19th Century Botanic Gardens: https://candeloblooms.com/2015/11/05/favourite-late-19th-century-gardens-in-australia/.
Dahlias are bushy herbaceous tuberous perennials with a huge variety in size (from 30cm up to 1.8m), type and colour. They have lush foliage with pinnate leaves of a variety of greens and even dark foliage like the red ‘Bishop of Llandaff’, a chance self-sown seedling from the 1920s garden of Cardiff grower, Fred Treseder; or the burgundy flowering Mt. Noddy with its chocolate foliage. My ‘Ellen Huston’ dahlia also has wonderful dark foliage. Sometimes the buds look positively metallic after rain! The flower colour varies from burnt red or scarlet to a softer red.
Flamboyant, showy and long-flowering, dahlias bloom all Summer and Autumn from November to May. There is a huge variety of forms including : Single; Cactus; Laciniated; Ball-shaped; Pompom; Waterlily; Peony; Collarette; Stella; Orchid; Anemone; Baby Dahlias; Decorative and Novelty. See:http://www.dahliaworld.co.uk/dahlia.htm for more information about their classification. Colour ranges from yellows, golds, oranges, reds and burgundy to pastel pinks, purples and whites, but there are no green, blue or black ones!
Phylogeny : Dahlias belong to the Daisy family Asteraceae and are closely related to Daisies, Sunflowers, Crysanthemums and Zinnias. There are 30 species and 20,000 cultivars. They were bred from single species dahlias : D.coccinea; D. Rosea and D. Pinnata and named after the Swedish botanist Andreas Dahl (1751-1789). Famous breeders include : John Menzel (Winkie Dahlias); Keith Hammett from New Zealand; Jack Gott from Britain and the Verwer brothers from Holland.
Origin : Native to Mexico and Central America, dahlias were imported to Western Europe by the Spanish.
Growing Dahlias :
While some sources state : ‘full sun’ as a requirement, the Dahlia Society of Australia advises that the best position is one with morning sun and afternoon shade, probably because our Australian sun can be so strong in Summer and burn the blooms. They do grow well under filtered light and under 2.4m high shade cloth eg White and Sandstone 50 percent cloth.
They also like a moist, rich, well-drained soil. Dahlias are very sensitive to too much or too little water, so good drainage is essential. They prefer a soil pH of 6.5-7. I also read that it is important not to water the dahlia tubers until their stems are 15cm high.
Dahlias are greedy feeders, especially in the warmer months. Organic sheep or cow manure should be dug into the ground 2 weeks before planting. Do not use poultry or pig manure, as it is too strong for the developing root system. Fertilize in Spring, as well as in the warmer months, with a balanced fertilizer with a ratio of 8:4:8 for Nitrogen, Potassium and Phosphorous. Do not use too much nitrogen as this will encourage leaf growth and less blooms. Weak weekly applications of a seaweed based formula (for example, watered down Seasol) are beneficial for root development and serious growers use small amounts of sulphate of potash and sulphate of iron to encourage strong growth, vibrant colours and more blooms. Some swear by water-soluble tomato food. An 8cm layer of organic mulch will also prevent water loss and protect the tubers.
Many of the larger varieties will need staking to support the lanky stems, especially with the weight of the flower heads. Tie the stems to canes with twine or use a metal cradle, trellis or tomato hoops. It is important to put the stake in before planting the tubers, so they are not damaged. Pinching out the young growth will also produce a sturdier plant.
It takes 8 weeks between planting and flowering. The Dahlia Society of Australia suggests planting tubers 2 weeks either side of Melbourne Cup Day ( ie 1st week in November), when the soil temperature is rising and there is no danger of frosts. In frost-free coastal areas of Queensland, dahlias can be planted in September. Exhibitors often plant in December for a March flowering to escape the heat in time for their show circuits.
Dahlias make excellent cut flowers. There is no need to bash the ends or plunge stem ends in boiling water. Just put cut dahlias straight into a bucket of water as you cut them, then recut their ends on a diagonal and arrange in a vase of water with added preservative. Cut blooms last well- at least a week- and water should be changed every 3 days and the stems recut.Dead-heading spent flowers on the plants will encourage the formation of more blooms and extend the flowering season. Make sure to cut the flowering stem right back where it joins the main stem.
The more compact varieties can be grown in pots with an underskirt of lower growing plants.Cut dahlias back to the ground in late May or early June. If the soil gets wet in Winter (risk of rot) or frosts are severe, or you need the space for Winter and Spring annuals, lift the tubers and store them in the shed in a shallow box covered with cane mulch or potting soil to prevent them from drying out, then plant them out again in September or October. Alternatively, wrap the lifted tubers in newspaper and check occasionally for rot. Otherwise, leave them in the ground and protect from light frosts with a heavy layer of mulch.Propogation :
Dig up and divide every 3-5 years, so they don’t get overcrowded or produce less blooms. Dig up in September before they start shooting. Divide into portions, each with a part of last year’s stalk attached, otherwise they won’t regrow. Replant in soil with lots of compost and decayed manure. Make sure you put your stake in first before planting the tuber portion. Smaller tuber divisions develop roots quicker than larger pieces. Place the tubers horizontally 10 cm deep and 50mm away from the stake with the eye higher than the tail. The Dahlia Society of Australia website gives detailed information on planting tubers. Below are photos of my dahlias : ‘Meadow Lea’ a Waterlily-type Dahlia and ‘Ellen Huston’ (red), a decorative type.Dahlias can also be propagated by cuttings of the young shoots in Spring. These cuttings develop very quickly into new plants, which are often stronger and healthier than those grown from tuber division. They can also be grown from seed and the offspring often look nothing like their parents. It’s a great way to develop new varieties. To save seed, remove the dead petals of the spent flowerhead to reduce the risk of botrytis, then when the flowerhead is dry, remove the mature seed and plant the following Spring.
Pests and Diseases :
Snails and slugs like the fresh shoots in Spring. Two-spotted mite can cause leaf distortion. Other pests include : thrips and aphids; white fly; cut worms and meal bug, but generally dahlias are pretty healthy. They can also be attacked by powdery mildew. Viruses can stunt the plant and distort leaves, but unfortunately, there is no cure and infected plants should be removed.
Tree Dahlia Dahlia imperialis
Another stunning dahlia, which is huge and a very dramatic addition to the garden. Native to Mexico, Central America and Colombia, it is hardy to Zone 8, though for longest flowering, it is best grown in frost-free climates.
Description : The tree dahlia is a herbaceous perennial 3 – 5 m tall with thick, hollow, bamboo-like stems, a large tuber, large bipinnate leaves and pendulous clusters of single lavender flowers with yellow centres in Autumn and Winter. There are single purple, pink and white varieties and a double white form is also available. The tubers can be bought from Diggers’ Seeds or Yamina Rare Plants. The butterflies and bees love the flowers! They flourish in most areas from the subtropics to cold regions.Growing Tree Dahlias :
They are easy to grow and propagate and very fast growing, as you will have seen in photos of my plants over the last year. Real Jack-in-the-Beanstalk type plants! They grow best with the support of a wall or fence and may need staking as their brittle stems easily break in the wind. Nylon ties are good because they stretch as the plant grows. Nipping out the tips when the canes are 1m high will result in a shorter plant, which is more resistant to wind damage. For a more compact plant, prune the soft new growth by a half to a third in early Summer and shorten 20-30cm shoots to 10cm. However, I love the appearance of the pendulous blooms and looking up into their sunny soft lavender faces ,which stand out against the deep blue sky. The little buds are so sweet!
Like all dahlias, they love a sunny spot with rich well-drained soil and shelter from wind and frost. They prefer a slightly acidic soil with a pH of 6.1-6.5. Despite their propensity to wind damage and the fact that they flower late Autumn in the very last frost-free week of the season, hence experience a very fleeting flowering season, before crashing to a black mangled mess with the first frost, I still love my Tree Dahlias and wouldn’t be without them- that said, I probably wouldn’t plant them in the first place with our Winter frosts! Last year, they flowered from 15-26 May, being hit by the first frost on my Mum’s birthday! But their blooms are so pretty and silky and their fragility makes them even more special!!!
Prune the canes in Winter back to almost ground level and cover well with 8-10 cm compost or manure, then mulch for frost protection over Winter.
To propagate, take a piece of stem with one, preferably two nodes, and plant horizontally in the ground 20cm deep in Winter. They can also be propagated by taking tip cuttings in Summer, transplanting intact tubers or seed. It’s that easy! Here are some photos of the growth of our Tree Dahlias over the last 3 months from the end of Spring 2015 through to the present day as seen in my previous blog posts:
No garden should be without at least one Dahlia. We have been enjoying the generous blooms of our dahlias : orange ‘Meadow Lea’ and burnt red ‘Ellen Huston’ all Summer and Autumn long ! I know that I have well and truly caught the Dahlia bug, as I could not wait till next Spring to try out my friend’s Dahlia seeds. I think I might have got away with a late Autumn crop! The seeds struck well and the little plants are positively zooming along, so I really hope that I get to see the flowers, as my friend assures me that the colour combinations are amazing! The photos below show the new seedlings in early March, then the emerging blooms this week.Here is another beautiful water colour from my daughter, a fitting tribute to such a beautiful flower!