Up and down the country, rose growers would have spent the summer months busily propagating rose plants for sale in winter 2019. Yes, that right, a whole two years away before they reach garden centres and nurseries.
There are several reasons why budding is used as a form of propagating roses. From a commercial view, it is a very efficient method of propagation as it can produce top grade plants in the shortest amount of time and with the least expense. Each eye is capable of producing one plant while propagation by cuttings usually requires 3 – 4 eyes per cutting.
Root formation and development is also another reason why roses are budded. With plants produced by cuttings, the development of roots is often slow and erratic, which results in a poorly developed root system and leads to problems with the establishment and growth of such roses. With budded roses, most understocks readily form a good, strong root system and this makes the whole process for the grower much easier.
Propagating roses by budding also allows different forms of roses such as standard, weeping and pillar roses can be propagated and grown with reletive ease. Without budding, it would be much more difficult and expensive to train roses into desirable plants.
When selecting a rootstock to use when budding roses, there are a number of characteristics that growers look for in order to grow the best possible plants but not one characteristic stands out in importance from any other.
In no particular order then, the desired characteristics of rootstocks include vigour, a long budding season, ease of propagation, lack of suckers, disease resistance, a well branched root system and long, straight stems with firm, thin, pliable bark that will hold the bud in.
The main rootstock used in rose production in New Zealand is Rosa multiflora or various strains derived from it and most budded plants you will encounter will be on this rootstock.
Rosa multiflora is a fast growing, high yielding rootstock with thornless stems and a fibrous root system. Plants are easily propagated by cuttings, produce very few suckers and are highly resistant to diseases.
The main disadvantage of Rosa multiflora is that it has thin bark that often results in buds being blown out by our frequent strong winds, although the bark often thickens late in the season that prevents budding.
One nursery in NZ also uses Rosa laxa as a rootstock, which is the main rootstock used in the UK and parts of Europe. Plants grown on Rosa laxa roots are more compact, have better flower colour and have good bud adherence. It also produces a good root system and throws virtually no suckers.
Although budding has been widely practised for many years, its use in the future will be limited by the avalibility of skilled people who are able to do it on a commercial scale. It is becoming harder and harder to find such people and because of this, the cost of budded roses will increase in the future.
Looking ahead, it is likely that more and more of the new cultivars to be released will be propagated by cuttings right from the time they are selected as seedlings in the breeder’s glasshouse – if they can’t be grown by cuttings, then they won’t be sold commercially.
In the Rose Garden for April
- Test your pH of your soil. It should be around 6 – 6.5 or slightly acidic.
- Prepare new areas for plantings. Dig over and add compost ready for winter planting. If planting where roses have been before, swap the soil for that in another part of the garden.
- Order new seasons roses for winter planting from garden centres and rose nurseries.
- It’s still a good time to take cuttings of roses.
- If the autumn rain has not arrived, keep watering your roses but do not dead head now.
By Hayden Foulds
Hayden also serves as Deputy Chairman of the World Federation of Rose Societies Rose Trials Committee amongst other rose endeavors.