When Do Tree Dahlias Bloom?

Bloom Time

• The flowers of tree dahlia are pendulous in form and daisy like, blooming in shades of light lavender, rose purple or white. The plant flowers profusely during late fall, producing 150 to 300 flowers. The size of the flower head measures anywhere between 3 and 6 inches in diameter. The center disk of the flower is yellow, and the flowers contain flat, papery seeds.

Plant Description

• Tree dahlia has a mature height of about 20 feet and is woody in growth, unlike the more commonly grown herbaceous dahlia varieties. Like other dahlias, tree dahlia also has tuberous roots. The stems or canes are unbranched except near the top where most of the branches and flowers grow. The large, compound foliage is 2 to 3 feet long and bi-or tripinnate. Each midrib has four to six paired leaf branches growing from it.

Stems

• The plant has distinct, bamboo-like stems or canes that are hollow except at the nodal sections. The canes are filled with edible, watery sap effective in quenching thirst. In Mexico, the natives refer to tree dahlia as acocotli or the water cane. The canes are the main method of propagating new plants. To propagate, cut cane into 20-inch-long section with two nodes per section. Dig a 3-inch-deep trench and lay the cane horizontally in the trench. Cover with soil. The new plants will start to grow from the nodes.

Cultural Requirements

• The fast-growing plants grow well in most geographical locations including areas with cold or subtropical weather. Plant in full sun but avoid areas of high wind as the brittle canes break easily. Stake the plants in high wind sites. Plant in a well-drained, moist soil amended with manure or compost. All dahlias grow optimally in rich soil and have a high fertilizer requirement. Mulch with decayed animal manure; this continually provides nutrients to plant and helps preserve soil moisture.