- Tubers
- Wait until after frosts to plant the tubers. An easy way to remember is to plant them in the ground two weeks either side of Melbourne Cup day. You can still enjoy earlier blooms if you start them in pots.
- Potted
- In cold climates they may experience some die back, they will reshoot when weather warms. Ideally wait until after frost before planting out. You can pot them on at any time.
- Botanical
- Dahlia x hybrida
- Plant Type
- Tuber
- Size (HxW)
- 80-150cm x 50-100cm. ‘Dahlegria’: 45-60cm x 25-40cm. ‘Happy Days’, ‘Dreamy’: 20-45cm x 20-40cm. ‘Mystic’, ‘Sincerity’: 50-80cm x 40-60cm. Grandalias: 30-45cm x 30-55cm.
- Depth & Spacing
- Tubers: Lie the tubers lengthways with the ‘eyes’ (growing tips) pointing up and cover with 5-10cm of soil. Space 50-100cm apart depending on variety and type of planting. We don’t recommend pots for large forms as they are such big, hungry plants.
- Potted
- Plant at the same depth as in the pot, be gentle with the tubers as you move them. A 20-40cm pot would be ideal and give a nice, full display.
- Soil
- Humus rich, moist, well drained soil is ideal. Improve poor soils with some well rotted manure/compost prior to planting – Dahlias are hungry plants. Choose a good quality potting mix in containers.
- Aspect
- Full sun to semi shade - they need at least six hours to flower well.
- Climate
- Cool to Sub Tropical
- Frost
- Half hardy. Hard frost and moist soils during dormancy can damage the bulbs, if in doubt they can be lifted.
- Water
- Tubers: After planting, wait until you see growth before you begin watering – if they are too wet before they initiate growth it can leave them open to rot. Keep moist in active growth. When the plants have finished flowering, cease watering, to allow the tubers to mature for lifting.
- Potted
- Pay particular attention if you are growing them in pots, you will need to ensure you water well once they are up and growing, if they dry out, they will sulk and you won’t get a good display. You will also need to add fertiliser regularly as per the directions on the pack. Fertiliser: Dahlias grow quickly and flower abundantly so are heavy feeders, we recommend applying a well balanced fertiliser prior to planting. If they are left in the ground each year, top dress in winter and summer. A tomato fertiliser is a good choice.
- Flowering Time
- Summer to autumn (December to April as a rough guide) though they often flower longer and this can be dependent on climates.
- After Flower Care
- Remove spent flowers to encourage further flowering. If your ground freezes, or the soil remains damp during their dormancy we recommend you lift them every year. Store tubers during winter in a dry airy position. Plant again anytime from June to November (unless your ground freezes). Tubers left in soggy ground may rot. If you are growing them in pots, simply place the pot under an eve/shed and bring them out again as they shoot. In pots, unless they are well cared for they may need to be treated as annuals.
- Notes
- The taller varieties, and the Dinner Plates may need staking, doing this at the time of planting will avoid root disturbance later on. Keep plants well ventilated to avoid mildew. Don’t be concerned if you have a small tuber, it will set roots more quickly than large tubers and establish easier. The larger tubers have a pre-existing food storage so will form roots a little later, taking longer to establish. The size of the tuber can also depend on the variety; all our Dahlias are guaranteed of flowering size.
You can pinch your plants when they reach around 20cm with four sets of leaves, snip off the top main stem and it will encourage more lateral buds (this will delay flowering by a week or two but you will have more blooms). To increase the size of the flowers, nip out the side buds as soon as they appear.
