Propagation Group, Victoria Rhododendron Society

by Bill McMillan October 2000

History

Many members of the Victoria Rhododendron Society have grown rhodos from seed or cuttings, but the Propagation Group sprang from the interest of one member, Ken Webb, in getting information and help toward propagating these plants.

Ken arranged a meeting of interested members of the society.The first group was small, consisting of Ken, Norm Todd, Margaret Buffam, Joe Harvey, Karen and Burns Morrison, Judy Gordon and Nancy Thompson.Now there are nearly 20 people involved, and most have propagators, ranging from simple boxes with heating coils to sophisticated set-ups that fill a room.

Purpose

The members of the group wish to ensure that unusual rhododendron species and hybrids that exist in select gardens in the area do not disappearfrom the region when the plant dies or the garden is abandoned.Some of the plants propagated are provided for the VRS monthly raffle to raise money.A fortunate spin-off of the meetings are ‘off topic’ informal discussions and advice about gardening in general.

Where

Cuttings are taken from various gardens, usually with the enthusiastic help of the owner, from July through into winter months, depending on the plant being collected.Not all cuttings root, but those that survive are potted and grown on.Once they are established, the new plants are variously planted in the gardens of the individual propagators, traded among the group, donated to the monthly raffle or sold to raise funds for the VRS.Plants have beentaken from the Finnerty Gardens - mainly azaleas grown from Herman Vaartnou cuttings.This year, at the request of the Finnerty Gardens executive, the group is also attempting to propagate the loderi ‘Mrs. Josephine Firth’ for future U.Vic garden sales.

The Propagators

The set-ups of the members of the group vary from Rube Goldberg specials to sophisticated units with their own rooms, but all have certain common characteristics:a bottom layer, usually sand, containing a heating coil; a growing layer consisting generally of half coarse peat and half perlite, (albeit some also include a proportion of sand - Clint Smith uses only sand); a cover, to keep the humidity high, and lights, usually fluorescent tubes to promote growth.Once each year the group gets together and manufactures potting mix, used for transplanting successfully rooted cuttings.

When and How

Cuttings are collected beginning as early as July and as late as February, depending on the rhodo being collected.For example, deciduous azaleas and broad leaf rhodos are collected early, whereas many lepidote species can be collected late.Generally, all but three leaves are removed, and the remaining ones cut in half so there is less leaf mass to maintain.A fresh cut is made at the bottom and one or both sides of the stem are wounded to the cambium for about a centimeter.The stem is then dipped in rooting hormone and inserted into the rooting mix in the propagator.The humidity is kept at 100%and bottom heat raises the temperature into the 65 to 70 degree Fahrenheit (16 to 21 degree Celsius) range during rooting.Most systems use fluorescent lights on a timing cycle that varies in length from 12 hours upward.Once they are rooted, as evidenced by new growth or resistance to a light ‘tug’, they can be potted and moved to a greenhouse if one is available.In other cases, the cuttings are potted in the spring when they can be moved outdoors, but NOT into direct sunlight.A north facing area works well.To avoid the stress and root damage during potting, some of the group insert the cuttings into individual pots, rather than into a communal propagating bed.

Seeds

Growing rhodos from seeds poses different challenges and requires patience, because many years can go by before the first flowering.But it also offers rewards in playing a role in the development of the young plants.Joe Harvey has written on this topic in other issues of the newsletter.

Grafts

We have ventured into the realm of grafts with mixed results.However, grafting cuttings that are tender or do not root well onto a hardy rootstock offers promise.Evelyn Weesjes demonstrated techniques and wrote an article on this topic in a 1999 newsletter.If it is of interest, we can E-mail notes from a session the Propagation Group had with Clint Smith on this topic.