Grown from leaves

Sunday, 27 November 2016

Leaf cutting in progress

Plants are amazing things. They can be reproduced by sticking a stem into the ground, which will grow into a new plant identical to the original one. Despite all our human sophistication, we are not yet able to clone ourselves like that! Recently, I have discovered how plants can also be reproduced from merely a leaf.

Rhizomatous Begonia Connee Boswell, grown from a leaf from the garden of Margaret Chedra in Sydney

A number of months ago, a garden group to which I belong had a discussion on foliage plants, and members brought along a number of different leaves from their gardens to show. It was a fabulous meeting and it reinforced the idea of how important foliage plants are in our gardens. Amongst the leaves on display were two large and decorative rhizomatous Begonia varieties: one with stippled silver and dark purple markings ('Connee Boswell'), rather similar to the stunning shrub Begonia 'Little Brother Montgomery'; the other one with lime-coloured patterns on a brownish background (name unknown by me). How I desired those leaves! I was allowed to have them and I was told that if I put the leaves into a container of propagating medium and waited quite a while, the leaves would take root and give me some plants!

I had never taken leaf cuttings before so with some trepidation I did as instructed. I cut the main veins on the back of my leaves in a few places with a razor blade before I buried the stalk of each leaf in pots of my favourite propagating mixture, which comprises perlite and hydrated cocopeat. I find this holds moisture yet drains very well, and I have had good success with many stem cuttings using it. The leaves were lying horizontally on the surface of the mixture. I weighted them down with a few small pebbles so that the leaves would be in contact with the mixture.

My improvised incubator boxes for plant propagation

After watering the pots, I popped them into one of my homemade incubators: big, clear-plastic tubs with lids, and with holes drilled at the bottom of it for drainage. I keep them in a shaded spot so they don't overheat. After several months, I gently tugged at the leaves and was met with resistance. My leaves had developed roots! It seemed impossible, the stuff of science fiction, but it had really happened. I gradually exposed the pots to more air by lifting the lid of the tub a little more every few days, then eventually placed the pots on my propagating bench and repotted them into containers of potting mix. At this point, they both still looked like a leaf lying on the top of the mix.

Rhizomatous Begonia, name unknown, grown from a leaf from the garden of Margaret Chedra in Sydney

A few weeks ago, when inspecting my nursery of cuttings, I saw a group of baby begonia leaves arising from the surface of the pots, each perfectly formed and coloured just like the original 'mother' leaf! It was a thrilling moment. I have since learned that my method of laying the leaf horizontally on the surface of the propagating mixture is the 'slow' way of leaf propagating; if I had trimmed the stalk close to the leaf and inserted the leaf upright in the mixture, I might have had my new plants a lot quicker! Hormone gel or powder can be a useful aid for the cuttings. Some people actually cut the leaf up into pieces, each having a junction of two leaf veins near the base of the section, to end up with more plants.

Streptocarpus hybrid: these can be grown from leaf cuttings

Rhizomatous Begonia - which are wonderful groundcover plants for shaded spots in Sydney gardens, with myriad colours and patterns on their leaves - are excellent subjects for leaf cuttings. Other suitable subjects are Begonia rex (done similarly to rhizomatous Begonia leaf cuttings); African violets and Peperomia (use the whole leaf, burying the stalk below the surface of the compost); and gloxinia and Streptocarpus (cut the leaves in half and insert upright into the pot). Other suitable candidates are Acanthus mollis, and succulents such as Crassula, Echeveria and Sedum, which are best propagated by inserting them upright into the propagating mix. Other succulents - such as Kalanchoe - produce tiny plantlets at the edge of their leaves, which naturally drop to the soil and take root: this process can be expedited by removing a whole leaf with plantlets and laying on the surface of the propagating mix. They will quickly take root and begin to grow. Leaf cuttings like warmth, so spring or late summer are ideal times to take them. It is an intriguing way to make new plants!