JARS v64n2 - The Busy Person's Guide to Growing Vireya Cuttings

The Busy Person's Guide to Growing Vireya Cuttings
Mary Hare
Warrandyte, Victoria
Australia
This article was first published in the Newsletter of the Victoria Chapter of the Australian Rhododendron Society, and then in the Vireya Vine, November 2009

We live in a suburb northeast of Melbourne on the Yarra River. It is, probably, one of the highest bushfire risks anywhere in the world, rivaling the Dandenongs. The fires last February got very close to us, but we were saved by a wind change.

Okay, I love vireyas and want to grow as many varieties as I can, species and hybrids. Each new one I see, a greedy desire to acquire lurks in my mind. I love them perfumed, I love them with large heads of multiflowered trusses, I love the dainty littlies and the hanging baskets of 'Coral Flare'. Each vireya show I go to I see more that are so beautiful. Anne O'Connor paints one and, in the painting, I see subtle colours that escaped my eye when I looked at the plant itself. I know there is a limit and I have to be rational, but they are so attractive. Many are not commonly available commercially. I work full-time away from the house; I don't have a shade-house or misting/watering system, and besides there happens to be a drought anyway in our area (in case you haven't noticed). Solution, EASY! I grow the cuttings in water, on the laundry room window sill.

I take the cuttings whenever. They work best if I can take new growth just as it hardening but, if it's a matter of taking a cutting from a plant that is dying, you don't have the luxury of choosing the time that is most suitable. Take the cutting as best you can, dip it in a hormone rooting powder/solution, place it in a labeled jam jar and place it on a window sill where it will have good light. And wait! Depending on the plant and the season, the roots may grow in about five weeks (the quickest) or it may take a year. The longest a cutting took was two years but more of that later.

Are there variations that work best? Yes there are!

Cutting Choice

If you have the luxury of choice, then take the cutting from new growth just after it has hardened sufficiently. However, this technique has worked just as well with broken off bits that have been lying on the ground and it works well with very dehydrated growth from dying vireyas. If the cutting is dehydrated I immerse it in water in a basin until it has rehydrated - one to two days, no longer or the water penetrates the intercellular spaces in the leaves, replacing the oxygen and carbon dioxide and the plant effectively "drowns." Sometimes I scrape back the epidermal tissue on the base of the stalk to expose the cambium layer before I dip it in the rooting hormone, other times I don't. When I do then I find that the roots grow from where I have scraped away the surface tissue, but if I don't, then the roots grow just as fast from the bottom of the cutting. The roots grow just as rapidly either way - the only difference is where the roots form.

Root-growth Hormone

There are a number of these on the market. Try what suits you best. I started using a powder that Yates had on the market about 20 years ago. Nowadays I use "Clonex Purple." It works quite well but the jar of water does tend to grow an algal slime very quickly so I have to change the water more frequently.

Container

As long as it's glass so that you can see the roots, it doesn't matter. I daresay that if interior decoration on windowsills matters to you then you could buy a matching set of lead crystal vases but I find the odds and ends of jars from a local bottle dump work quite well - but then I use the windowsill in the laundry which my visitors do not frequent.

Labels

This is CRUCIAL!! I will admit that on the occasion when our vireyas were devastated by Colectrichum and we lost 45 of them over three weeks, we grabbed cuttings as soon as the next plant started to go brown and wilt. We ended up with four unlabelled unknowns and now have to wait until they flower to be sure of their identities. Do the label before you put them into the water. I use a sticky label on the outside of the jar (waterproof ink).

Position

Light is, of course, essential. My laundry windowsill faces south and has good light all day with only oblique direct sun on the jars early on summer mornings. I would not like to expose them to full sunlight in summer or they would cook.

That's how, now how successful? My success rate is over 90% for all cuttings to live, grow roots over varied time frames, be successfully transplanted into soil and to live for at least a year outside. I stopped counting after that as all the usual living hazards exist. So, yes, it is a most successful method with the minimum of effort. I do top up the jars of water each week and change the water when the look of the algal growth is annoying me. I have to move them once a week to dust the windowsill. If the weather is very hot (over 40°C (104°F) for 2-3 days in a row), I change the water completely because it has warmed up and would be likely to be low in oxygen, which as far as I know, the plant stems/roots need.

Time

The roots grow at very varied rates. One set of cuttings I acquired at "Emu Valley" in Tasmania were carted around Tasmania for about two weeks in a little water in a plastic bucket in the car. It was summer, so they were stressed somewhat. When we got home, I set them up as usual though and none of them died, but they did take two years to grow roots. I have noticed that when a cutting is fresh and placed into water, the water level drops quite rapidly for about two weeks and then slows considerably, and the cutting uses much less water from then on. I have a suspicion that the cuttings become somewhat dormant, a resting phase rather than growth, and that is why the marked change in transpiration rate. (I have checked that it is not due to evaporation rate from the water surface but that transpiration from the leaf surface definitely slows.) When the roots start to grow, they often match the growing season of the garden plants. Once the roots have appeared, they grow quite rapidly. I also suspect that plant cuttings in the same jar have some hormonal influence on each other. I am not so organised that each cutting has its own jar of water. My window sill space is limited, so I will sometimes put a new cutting in a jar with an older one already there. Once roots start to appear on one cutting in a jar, it seems to me that other cuttings in the same jar do speed up their development of roots also. So when the time comes for them to "leave the nest," I usually have about eight plus plants to transplant out into pots in the "nursery" (a sheltered spot with little direct sunlight where I will remember to water them through the hot days).