Profile: Tree dahlia
Botanical name: Dahlia imperialis
Commonly known as the
tree dahlia, this plant has similar habits to the regular garden
dahlia, but with one big difference it can shoot up to towering
heights in short time spans.
The delicate tree
dahlia bears huge leaves and shaggy lavender flowers with yellow
centres. Its stems are tall, straight and thin, much like bamboo
The dramatic, pendulous
flowers bloom from late autumn generally in
May and June.
There are a number of
species close to the D. imperialis, including D. tenuicaulis
, D. rudis and D. scapigeroides , none of which
are as large imperialis.
Parva Plants (email@example.com)
have a small range of tree dahlias for sale including
the fairly new cultivar, D. 'Timothy Hammett' (photo above).
Unlike other imperialis, this variety doesn't flower just in late
autumn but throughout summer and autumn. The plant is slightly smaller
in size and less pendulous, but the indiviudal blooms are, nevertheless,
Generally the tree dahlia
is a fairly easy plant to grow. Plant in a sunny spot with
shelter from wind and frost they can, however, withstand
light frosts. Their brittle stems can quite easily be broken by
gusts of winds, so it may pay to stake them.
They do best in moist
soils that are well drained. Never plant in an area that is prone
Although they die away
annually, they will need a bit of pruning throughout the year. The
best time to give them a prune is just after flowering (in winter).
They are fairly pest
resistant, although powdery mildew can attack some plants, and moth
caterpillars may take a liking to them.
To propagate, take stem
cuttings. Place 30cm long cuttings, each with at least two nodes,
in soil either horizontally or vertically.
with permission from NZOOM Home and Garden content,
from the previous
The views expressed here are not necessarily those of the RNZIH