Dahlia imperialis alba is one of the tallest varieties that we offer growing up to 10 ft in the UK. It has however been known to grow up-to 15 ft in its native South Africa. Dahlia imperialis alba is a late flowering single flowered dahlia and has pure white flowers.
Plant Indoors: The Dahlia tubers of Imperialis can be started off indoors from January to March.
Plant outdoors: Plant tubers into the garden or containers after the fear of frost has passed. This is normally towards the end of April but can be earlier in the south and in coastal areas. Alternatively plant direct into the garden when the soil has warmed up and the fear of all frosts have passed. Cultivate soils to a depth of 20cms and plant tubers so that the top of the tuber is 5cms below the soil surface. Soils are best manured in the winter before planting as the young roots of dahlias do not like fresh manure around them.
Dahlias can be left out over winter in well drained soils, just mulch to give added protection.
Remove dead flower heads to ensure a summer of flowers and remember to feed during the leaf and flower stage with something like bone meal or tomato feed.
Flowering Height: 8-10 feet (240-300cm)
Flowering Period: July to first frosts.
Soil type: Free draining humus rich soils, in heavier soils add grit to help with drainage.
Aspect: Semi shade to full sun.
For further growing advice visit Tims tips/dahlias on you tube.