The dahlia imperialis or tree dahlia is a beautiful herbaceous perennial flower.
In summary, what you need to know:
Last name : Dahlia imperialis
Family : Asteraceae
Height: 2 to 4 meters
Exposure: Sunny, partial shade
Ground: Regular enriched
Flowering: September to November -Frost resistant : -5°
- Read also: how to grow dahlia properly
Sometimes called a giant dahlia, it can reach 4 m in height!
Planting dahlias imperialis
Dahlia imperialis flowers in winter but cannot withstand temperatures below -5 °. So make sure your climate allows it before you plant it.
Plant the dahlias imperialis bulbs:
The dahlia imperialis is ideally planted in april and may, after all risk of frost.
Plant them at a depth of about 10 cm, keeping a spacing of 100 cm between each dahlia, because the dahlia imperialis has need sun and likes to be at ease!
- Avoid windy situations which could break the stems of the dahlia imperialis.
- A mixture of potting soil for flowering plants and garden soil is ideal for planting.
- Dahlia imperialis needs to be staked when planting.
- Water regularly the 1st year but without excess because the dahlia dreads humidity.
- Add flower bulb fertilizer in subsequent years.
- Mulching helps protect the bulb in winter.
Multiplication of the dahlia:
- In sowing, prefer a seedling in terrine from March, transplant in April and put in the ground in May.
- Multiplication by tuber division in spring.
Caring for dahlias imperialis
The dahlia imperialis is a flower that requires some care to see it bloom year after year.
The dahlia imperialis appreciates rather warm, rich and well-drained land.
The tree dahlia also enjoys being watered in summer but fear excess moisture in the soil which can destroy the plant.
- Remove faded flowers as you go.
- Once the stems are completely wilted, cut them as short as possible.
- Dahlias imperialis are resistant to temperatures in the order of -5 °.
- In winter, it is important to protect the feet with a plant mulch.
If you are concerned about severe frosts:
After flowering, at the beginning of winter, bring in the tubers from the first frost and store them in a dry place protected from light until the following spring.
Watering the dahlia imperialis
As mentioned previously, watering the tree dahlia is important because it should be regular but never excessive.
One of the biggest concerns with this plant is root rot. So you need a well-drained soil.
- Water the dahlia imperialis, taking care not to wet the foliage. You will thus avoid any risk of fungal disease.
- Water preferably in the evening to avoid evaporation and also save water.
Dahlia imperialis in winter
The dahlia imperialis does not resistant to severe frost.
If you live in an area where it is frequently over -5 ° C, you must bring in the bulbs at all costs before the first frosts.
The operation takes place after flowering and before the temperatures drop below -5 °
- Wait until the foliage has completely wilted and cut 10 cm from the ground.
- Pull up the rhizomes and dry them 2-3 days in the sun.
- Clean them with a brush.
- Store them in a cool, dry place, protected from light.
- Replant them after any risk of frost, in the spring.
In other regions, protect your tubers with a mulch of dead leaves, for example.
Diseases and parasites that affect dahlia imperialis
The main difficulty that affects the dahlia imperialis is the rotting of the tuber.
This happens when the soil is too wet and not draining enough to drain excess water.
It also leads to various mushrooms as'powdery mildew or gray rot.
Side parasites, the dahlia may be subject to aphids
All you need to know about the dahlia imperialis
Originally from Mexico, the dalhia imperialis or dahlia in tree offers a very particular stem resembling a bamboo.
Its flowers are just as beautiful, a pretty pink they can also be white, and always large in size. The flowers of the tree dahlia can reach 20 cm in diameter.
In temperate climate, the foliage is persistent.
It is also called Imperial Dahlia, tree or arborescent dahlia, Lehmann's Dahlia or bamboo Dahlia for the strong resemblance of its stem to the latter.