Dahlia Growing Guide

Adored by millions over the world, Dahlias certainly know how to make an impact. With flower colours from just about the whole rainbow, Dahlias are one of the easiest and most rewarding flowers to grow. Dahlias will reward you with endless stems of flowers for the vase, provide clouds of colour through the warmest months of the year, and almost seem to thrive on neglect.

Once picked, blooms last in a vase for a number of days; changing the water every day or two will increase the flowers’ life.

3 steps to planting dahliaS


Dahlias will thrive in full sun and can be grown in a little shade if required. You will find they won’t flower as well with fewer sunshine hours though. They are relatively tolerant of a wide range of soil types, from sandy through to loams, as long as they are fertile. Once established they will endure dry periods with little or no extra water, however a moist, fertile soil will enable the plants to establish quicker and will encourage a more prolific flowering period.

If you live in an area that gets frost, be patient and plant out once the last frost has finished. Don’t be tempted to get them in too early as the new growth is delicate and soft and won’t cope with frosts. 

Some favourite varieties to look out for are Cafe au Lait, Art Nouveau, Copper Queen, Dream Catcher, Edna Brown, Jim’s Passion, Kotare Buttermilk, Mystic series, Rural Belle, Rural Lady, Taratahi Sunrise, Titoki Point, Tranquillity, True Love, Tui Regan, Tui Gem and Twinkle.

Like building a house a good foundation is the key to success in your garden. The better the soil, the better your plants will grow. If you are starting with an existing garden bed dig in organic matter like Tui Sheep Pellets and Tui Compost to your soil. Then you can add a layer of Tui Flower Mix

Dahlias can be grown in large pots, ensure the pot is at least 30L in size. 


The best times to plant are early in the morning, or late in the day so the plants aren't exposed to the hot sun straight away. Always water plants well before and after planting.

Directions for planting in garden beds

  • Water plants thoroughly before planting and allow to drain.
  • Dig a hole, approximately twice the depth and width of the root ball of your plant.
  • Gently loosen the root ball of your plant and position the plant in the centre of the hole.
  • Fill in with Tui Flower Mix.
  • Press soil gently around the base of the plant.
  • Water your plant well and continue to water regularly.

Directions for potting plants

  • Water plants thoroughly before potting and allow to drain.
  • Half fill your container with Tui Flower Mix.
  • Gently take the plant from the current container, loosen the root ball and remove any loose or dead pant material and roots.
  • Position the plant in the centre of the new container and fill with Tui Flower Mix up to 3cm from the top.
  • Gently firm mix around the base of the plant. The mix should be at the same level on the plant as it was in the previous container.
  • Water your plant well and continue to water regularly.


Feed your plants and they will reward you. Replenishing the nutrients used by your plants ensures your plants grow to their full potential. Feed your Dahlias with Tui NovaTec® Premium Fertiliser in spring and autumn.

A well-watered, well-nourished garden will have a better chance of keeping insect pests and diseases at bay. While your Dahlias are growing regularly apply a dose of Tui Organic Seaweed Plant Tonic to give them a welcome boost.

Dahlias need plenty of room to flourish, don’t be tempted to plant them too close together. Check to see how big your Dahlia will grow when spacing out new plant beds. Use the height spacing system if you’re unsure e.g. if your plant grows 1 metre tall then plant them 1 metre apart.

As the plants begin to grow, it’s a good idea to pinch out the young growth tips to encourage more branches, which will provide more flowers.

Deheading will prolong the flowering season. At the end of the season the plants will begin to die down; don’t be tempted to cut off the foliage to tidy up the garden before the plant has totally died down.