Green Fingers Summer Dahlia Maintenance Guide for New Zealand

Summer is the main growing period for Dahlias and while this is the main time of year for healthy lush growth and beautifully colourful flowers, it is also the main time of the year for pests and diseases. This guide will give some tips and tricks to get the most growth from your Dahlias while also helping to protect your plants during their most vulnerable period.

Watering your dahlias during the dry summer months

Summer in New Zealand can get hot and dry, especially in the Otago and Canterbury regions. Due to this Dahlias will need an extra sprinkle of water every now and then. The best method for watering Dahlias is to ensure you give them a real good soak, at least twice a week. This gives the plants enough water to thrive, while also allowing the soil to go through dry periods. This prevents any rotting from occurring and also causes the roots of the Dahlia plant to spread further and deeper.

Dahlias are hungry plants – Do Dahlias and the soil still need fertiliser?

Yes! As Dahlias continue to grow and produce more and more flowers, the nutrients required to produce this growth and an abundance of flowers needs to be replaced. This can be easily achieved with a foliar fertiliser designed for Dahlias such as Green Fingers Dahlia Foliar Fertiliser, which helps return a lot of the nitrogen used for lush growth and also provides enough phosphate, potassium, and other required micronutrients to continue to provide the best flower display possible while also remaining healthy. A lot of the goodness in the soil can be used up by lush dahlia growth, and this goodness can be returned by using a combination of Green Fingers Liquid Seaweed alongside Green Fingers Liquid Humic. Healthy soils ensure a plant can uptake all the nutrients it needs and alongside a foliar spray this will create a strong, robust, and healthy plant. Like humans, stronger, healthy plants have stronger defense systems which enable them to better deter pests and diseases and the problems that can come with them! Use the best Dahlia fertilisers to keep your plants happy, healthy and pest-free.

Pests and diseases are abundant this year! What can you do?

Even the healthiest plants can succumb to pests and diseases. This is especially true to young newly emerged Dahlias which can be easily savaged and destroyed by slugs. The best method for these little pests is using Quash slug bait which is a human and animal friendly product made using a form of iron to kill slugs. Quash also easily breaks down in water and then provides iron to the soil and eventually plants. New Zealand has also had a warm, wet winter, which has not only led to an abundance of insect pests, but diseases such as powdery mildew seemed to have struck a lot earlier. Fortunately, the phosphate in Green Fingers Dahlia Foliar Fertiliser is enough to deter and prevent powdery mildew, however, if you don’t use this product a simple spray of copper oxychloride will also help deter and prevent powdery mildew as well as a host of other diseases.

Dahlia with a bad case of Powdery Mildew

Want to enjoy the flowers inside? Here is the best method to get cut-flowers from your Dahlia

Cut flowers from Dahlias are a must! They not only help beautify your home, but consistently deadheading Dahlias encourages more blooms from your plants. Flowers are the plants way of recreating via seed, so by consistently removing these flowers before allowing them to seed, forces the plant to continue flowering in an attempt to produce seed. If left alone seeds will be produced in the flower which can then be germinated and planted the following year, although the seeds will not be true to parent.

The best method we have found for cut-flowers is to begin by finding a flower that is healthy and open. Unlike peonies, Dahlia flowers will not open once picked. Once you have found your desired flower, make a straight horizontal cut on the stem just slightly above a set of leaf nodes. Once inside with all your harvested flowers, make another fresh straight cut and put about 4-5cm of the cut stem into hot water and let them sit there for about an hour. Next simply strip of any leaf that is too low for the vase and any other leaves that may distract from the flower. Just remember to change the water every 2-3 days to prevent bacteria building up and your cut-flowers will remain beautiful, vibrant, and full of life for at least 5-7 days!

Summer is the time to enjoy your garden and Dahlias, and while it is a busy season, don’t forget to stop and smell the roses! Leave a comment below and let us know your favourite type of Dahlia!