Guide to Planting Dahlias

Dahlias are beautiful flowers and a firm favourite among gardeners. As they come in almost any colour and a range of shapes, they make the perfect addition to your flower displays. They are great for bringing a splash of colour to your garden from July to October and are suited to all garden styles and can thrive in flower beds and containers alike. If you are new to gardening or haven’t had experience with these flowers before, here is our guide to planting Dahlias. 

Where to grow Dahlias 

Dahlias as a whole need fertile soil that is moist but also has great drainage. Whilst they need a sunny spot, they also require some shelter. Ideally, the soil should then be enriched with organic matter like well-rotted manure. If you are planting directly into a container, ensure you are using high quality, peat-free multi-purpose compost for the best results. 

Growing Dahlias from Tubers 

Whilst you can purchase Dahlia plants in the Summer, many gardeners opt for growing them from tubers instead. To do this, the tubers are potted in late March to early April and then placed in the garden in May once the risk of frost has passed and the soil temperatures are warmer. Once the temperatures drop again, many people dig up their Dahlia tubers in Autumn and keep them indoors in their shed or greenhouse over Winter to avoid frost damage. Whilst tubers are a popular option, Dahlias can also be grown from seeds or cuttings if preferred.  

Despite being temperature sensitive which means gardeners have a bit of extra work to do, these flowers are worth the effort. As Dahlias bloom from mid-summer into Autumn, they appear in displays when many other plants and flowers are past their best, meaning you can have a colourful flower display in your garden for longer. 

Dahlia Watering Tips  

You don’t need to water the soil until the Dahlias plants start to appear, as you have already planted the tubers in moist soil. If you overwater them you can cause the tubers to rot  

Once the plants have started to appear, water them sufficiently 2-3 times a week. Ideally use a sprinkler for a deeper watering 

The larger Dahlias will need extra attention. The large flowers can capture a lot of water when it rains and can also get damaged in the wind. So it is important to ensure they are secure and not overwatered. 

Once the plants are 12 inches tall, pinch off the top of the main stem. This can help stimulate new growth  

Pests can be an issue however, chemical pesticides should be avoided in order to protect pollinators. To help keep pests and diseases at bay, keep the foliage of the Dahlias as dry and possible. This is why 2-3 deeper waterings are more effective than daily.  

Other top tips for growing the perfect Dahlia 

Choose the perfect place to plant Dahlias based on the variety you have chosen. Dwarf varieties make the best choice for the front of flower beds. The taller varieties should be placed at the back of displays and are great for bringing an extra layer to your displays. 

Dahlias also make amazing cut flowers. In fact, the more you cut them, the more flowers you can produce 

A lot of Dahlias unfortunately do not attract pollinators because of their complex flowers. Therefore, where possible, include some single-flowered varieties to help bees and butterflies  

Dahlias are relatively fragile and require huge amounts of sunshine, meaning that they need protecting during the cold Winter months  

Ensure you provide Dahlias with plenty of space to grow. Planting them approximately 60cm - 75cm apart can help give them enough space 

For planting taller Dahlias, ensure you provide them with some support such as a bamboo cane.  

Ensure you deadhead regularly. Once the flowers have passed their best, remove them to help encourage new flowers to grow whilst also ensuring the display looks neater. 

Cut Flowers 

One of the benefits of Dahlias is that they grow extremely quickly and make amazing cut flowers. Harvesting the flowers can actually be good for the plants and encourage them to continue to flower. This is great news for those who love to have fresh flowers in their home. They can also make great treats for friends and family. 

With all the options available, it is clear to see why Dahlias often make appearances in the most striking and colourful flower displays. Not only do they look amazing, they can add a range of height and colour to your garden whilst also making fantastic cut flowers.  Following this guide to planting dahlias, you can reap the rewards of this beautiful flower for years to come. 

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