Cup and Saucer Vine

 

Cobaea scandens is a tropical perennial vine in its native Mexico. The bell-shaped flowers are 2in or more in diameter, the green calyxes remain at the base of the flower and become the saucer - hence its common names, cup and saucer plant or cathedral bells.
It is grown in cooler climates as an annual which due to its vigorous growth, produces vertical cover and large exotic looking blooms at the end of the summer and into the autumn.

Last night we had the most severe frost of the winter so far, and up till now both my varieties of Cobaea have survived and continued growing. There was even a few flowers up until two weeks ago. The date today is 29 December!

Planted as seed in early February 2013, indoors on heat they germinated well. The 'Alba' variety shown on the above left was slower and slightly less vigorous all the way through growth. The plants are easy to tell apart with the Alba having green stems on new growth and the purple variety has reddish purple stems. I planted approx. 6 vines in a clump. They are very badly behaved vines from a young age and will grab anything within reach with their slightly sticky, multifingered tendrils. Next time I will germinate them in their own pots with their own stakes.

My plants are on a trellis along a north, south axis so get the benefit of sun all day from either side as the sun moves over the garden. They have reached well over 20 feet and have started to explore the shrubs and trees planted along the fence.
The flowers are on longish stalks that hold them out in front of the leaves. The blooms on both strains darken to an inky purple with age, the 'Alba' is soon indistinguishable from the purple as the greenish cream colour is lost quickly. I couldn't detect a strong scent from the blooms, just a very faint sweetness. In their native Mexico they are pollinated by bats. Seed will set if they are pollinated by a large insect such as a Bumblebee.
The leaves are 4in long, composed of four leaflets and a tendril with many little hooks on it, which it uses to climb.
Charles Darwin was so impressed he studied Cobaea for his book The Movements and Habits of Climbing Plants (1875).

If my Cobaea does not survive the winter (I have mulched it heavily at the base... ) I will certainly be growing it again.
It ticks all the boxes for an impressive tropical climber that makes good cover, has the most gorgeous big flowers and lasts well into the winter in a sheltered garden.