by Brian Denison
Aeoniums are natives of Madeira, the Canary Islands and North Africa, climates that do not experience sub-zero temperatures, consequently plants need protection in the UK during winter.
I insulated my greenhouse in November to accommodate them. I had to remove everything in the greenhouse to install the bubble wrap.
In Fig 1, I have just started to return the plants.
In the video below all the plants have been returned to the greenhouse and as you can see I have quite a few Aeoniums.
Many of them are the black Aeonium ‘Zwartkop’ but I also have several of the bright green species A. arboreum. The display in Fig 2 highlights the contrast in colour of the two Aeoniums.
Another species I have is called A. ‘Blushing Beauty’ given to me by our late much esteemed member Roberto Renzi. This plant normally has pink tinges to the leaf tips, but it needs sun to develop the colour so the leaves are plain green in winter. My fourth and final species is A. ‘Sunburst’ purchased at Harrogate show last Spring (fig 3).
I have recently put together an arrangement of this Aeonium with Echeveria Peacockii (fig 4) . This is a succulent from the same family Crassulaceae and has similar cultural requirements.The display should look better when some growth occurs. The Echeveria was purchased from Merriments in East Sussex a couple of years ago. They had a superb display of several of them planted outdoors. I have already propagated my plant from offsets which were used for the Fig 4 display. The original plant and remaining offshoots can be seen in Fig 5.
One of the problems with Aeoniums is their quick vertical growth but they may still look stunning, as seen in the examples in figures 6 and 7.
When Aeoniums get leggy the tops may be cut off with say 50 to 100 mm of stem and rooted easily in a cutting mixture. The cutting must be allowed to dry for a few days until the wound has calloused before potting up. I like to use an upturned plant pot to ensure the stem remains upright – see this video .
Aeoniums are monocarpic, meaning they die after blooming. When Aeoniums form branches, not all the stems necessarily flower at once; the flowering stem(s) may be removed giving a good chance for the plant to survive. Out of interest Fig 8 shows an Aeonium in flower and fig 9 shows a flower on one stem which may be removed if desired.
It is also interesting to try to get Aeoniums to branch out. You can simply chop off the top (the removed stem can then be use as a cutting) and then ideally cut the stem down again leaving perhaps 50 to 100 mm of remaining stem which is then allowed to regrow (Fig 10). Another technique is to carve out the growing point but this it is not easy as the leaves are tightly packed. If successful, the plant produces new shoots as illustrated in Fig 11.
I have several tender succulents, so my greenhouse is maintained at minimum 5°C (see Appendix 1). To justify the equipment and cost, I try and use the facility as much as possible to overwinter tender perennials, cuttings, Pelargoniums, and some half hardy Fuchsias. Some of the latter are now up to 4 years old, so are of decent size and give a wonderful display in summer. I use Fuchsias quite a lot for summer displays because I have lots of shade. Fig 12 shows Fuchsia ‘Voodoo’ in a shady north facing position in early August. I trim and defoliate all my fuchsias for winter storage.
Now my greenhouse is fully utilised for a variety of functions, perhaps I am not so fixated about Aeoniums after all.
To maintain the greenhouse temperature at not less than 5°C, I use an electric fan heater. Although it has an anti-frost setting it does not control the temperature well enough. The Novatec thermostat in Fig 13 works incredibly well. The fan is set on the heat setting and is connected to the thermostat unit. It will only come on when the thermostat detects the temperature falling below 6°C. It will control temperature to an accuracy of +/- 1°C so will switch off the heater when appropriate.
In late spring the thermostat can be switched to cooling mode when required. The fan heater element is now switched off, but the fan remains operational. The thermostat is now set to an upper temperature limit which when exceeded automatically starts the fan to cool the greenhouse.
I can also monitor the greenhouse temperature in the house using a weather station (fig 14). I have two remote sensors one in the garden and one inside the greenhouse. I check every morning to see what maximum and minimum temperatures have been recorded.
Perhaps the most important implement however is the greenhouse door which is opened and closed as appropriate to hopefully minimise mildew etc as well as helping to control temperature.