Plant of the Month for August, 2017

 (dik-TAM-nus  AL-bus)

General Information:

Dictamnus albus always makes a big splash in the garden when it is flowering and even when it is not flowering it is a very interesting plant with good leaf structure.  Even the star-shaped seed heads are interesting. So why is this plant not seen more in gardens? It is very slow growing and I think it costs nurseries too much to get it to a saleable size. Fashions have changed and this fantastic plant has been left behind in favor of more modern plants. That is a real shame since few garden plants will match the presence of a mature Dictamnus.

Dictamnus albus, by Robert Pavlis

Dictamnus albus ‘Purpureus’: photo by Robert Pavlis

The most common name is gas plant, but some people also call it burning bush, dittany, and fraxinella. The name gas plant refers to the of fragrant, flammable oils produced both during flowering, and while it produces seeds. The fragrance is lemony and quite pleasant.  If you touch the plant, you will feel the oils produced. Some, consider this to be the burning bush referred to in the bible.

Is the gas plant really flammable? Have a look at this video.

https://www.youtube.com/watch?v=OH7u4xFmpP0

Before you go and touch this plant you should be aware that it causes phytophotodermatitis (ie skin reaction) for some people where exposure to sun produces blisters. I don’t have this problem and most people don't.

Dictamnus albus, by Robert Pavlis

Dictamnus albus ‘Purpureus’: photo by Robert Pavlis

The gas plant has a long, deep tap root which makes it very drought tolerant but also difficult to divide or move. It is best to leave the plant where it is, and grow a new one from seeds. But even this can be a bit tricky. When the seeds are ripe, they are shot out of the seed capsule as soon as you touch them. It is best to bag seed heads and wait until they drop into the bag.

Seedlings grow slowly, but are not difficult to raise. The plants are quite tough and should flower in 3-4 years. Once established, it will last a very long time.

Dictamnus albus, by Robert Pavlis

Dictamnus albus 'Alba': photo by Robert Pavlis

Available in three main colours, pink with stripes (D. albus ‘Purpureus’), white (D. albus ‘Alba’) and a much less common red (D. albus ‘Rubra’). I looked for a picture on the internet for rubra and could not find one. Several nurseries sell a so-called rubra, but the pictures are clearly that of Purpureaus. Does a red one really exist?

Website administrator's comment: The Royal Horticultural Society is the primary reference used by ORG&HPS for confirming the name of cultivars. RHS lists  D. albus var. albus and D. albus var. purpureus indicating they are varieties, not cultivars. In addition, they specify that D. albus 'Rubra' is a synonym for D. albus var. purpureus See RHS database

Life Cycle: perennial

Height: Plant is 60cm (2 ft) tall with the flower spike adding 30 cm (1 ft)

Bloom Time: Mid summer

Natural Range: Europe, North Africa and much of Asia

Habitat: open woodland

Synonyms:  Dictamnus fraxinella, Dictamnus caucasicus

 

Cultivation:

Light: full sun

Soil: fertile and humusy – but not fussy

Water: drought tolerant once established

USDA Hardiness Zone: 3 – 9,  prefers cool climates

Propagation: seed, division with care

Seedex availability (ORG&HPS annual Seed Exchange): usually

!

Sow immediately. The viability of these seeds is short or the species propagates best with fresh seed. Stored seed might be coaxed into germination with temperature cycling and patience.

J

Sow @4°C for 3 weeks, then place @20°C.
Robert Pavlis