How to Plant Peonies and Dahlias
Some plants, such as peonies, iris, cannas and dahlias, are often sold as bulb flowers, but they don't have a true bulb.


The plants grow from what is called a tuber or rhizome - a swollen root or clump of roots - like a sweet potato.
It acts in the same way as a bulb, storing up nutrients and allowing the plant to rest dormant through half the year.


It can be tricky to work out which way to plant these tubers and rhizomes. They don't have an obvious point, like a tulip bulb does, to point upwards. Look closely and you'll see tiny buds emerging from the root clump - these are the signs of new growth.


Plant your tuber with these bud shoots pointing upwards. When you do this, you'll see the old swollen roots and new white slender roots will automatically face down into the soil.


If your rhizome or tuber does not have any new buds or fresh roots yet, lay the tuber on its side when you plant it. The plant will be able to orient itself and grow in the right direction much more easily.


Here's our top tips for successful bulb planting


1. Many bulb flowers need well-drained soil to thrive – in Holland they grow them in pure sand! Add grit or gravel to your planting holes if your soil is heavy, or plant up into containers.


2. Leave the leaves! Let the old foliage die back completely, to feed the bulbs for next year’s flowers. But snip any dead flowerheads off so the plant doesn’t waste energy making seedheads.


3. September is the perfect time to plant summer-flowering bulbs, especially after frosts. The soil is warming up, encouraging growth. You can plant earlier in northern Queensland, and everywhere else right through Spring for an extended season of flowering.


Lasagne bulb planting for a layered effect

 

4. The latest way to plant bulbs is called a “lasagne”. (See picture.) Larger bulbs are planted at the deepest level and covered with a thin layer of compost. Medium sized bulbs go at the middle level, and small bulbs at the shallowest level. The plants will grow up between each other and create a full dense display of flowers in a small area.


5. If you plant bulbs into your garden beds, mark the spot so that when the plants die down completely, you won’t dig them up by mistake.


6. Summer bulbs make excellent potted plants. Plant them into pots, move them into prime positions while they are in flower, and tuck them out of sight to die down through autumn.