Escaped root stock

Many years ago, neighbours planted a row of flowering cherry trees on their roadside. Mark and I were discussing how long ago and he thought somewhere over 30 years, maybe even more. I recall when they first went in and they struggled for at least the first decade. There used to be quite a few more but these are the survivors.

We are not good territory for prunus and these were in a particularly exposed situation – windy, in other words. They may not have been planted very well but that is just a guess. To add insult to injury, I asked Mark if he could remember seeing them flower because it suddenly occurred to me that I had no memory of them in bloom yet we drive past them every time we leave our property. He couldn’t remember either so I guess we can conclude that the flowering is not anything remarkable at all, possibly occurring at the same time as the trees leaf up for spring. I shall try and take more notice this spring. They do at least colour up in autumn.

Two different growth forms on the same plant – one upright and one spreading

We can’t identify the variety but it is clearly not well suited to our climate and conditions. However, it is a named cultivar because these are grafted plants. How do we know? Take a look at this one in the row. It has the same spreading form as all the others but in the middle is this upright shape. That is escaped root stock.

There are many reasons for budding or grafting onto the roots of another plant. Some selected varieties don’t grow well on their own roots or can’t be struck easily from cuttings. Depending on the chosen root stock, it can either increase the vigour of the plant or it can dwarf it and slow it down. Fruit trees are often put onto dwarfing stock. If material of the chosen cultivar is in short supply, budding or grafting can make it go a lot further with a higher success rate in propagation. While it takes more technical skill to bud and graft than to take cuttings and the selection of appropriate root stock is very important, it is possible to get a higher percentage through the propagation process and to reach a saleable grade faster than from cuttings. Many plants are budded or grafted, Budding, by the way, is usually easier than grafting. Once the bud or graft has taken successfully, the original growth from the root stock is removed entirely.

When I looked at the base of the plant, it was clear that the upright section all came from one strong shoot close to the base – outlined here in red

Problems come when the root stock puts up a shoot that is allowed to grow and that is what has happened to this tree. Occasionally we get asked why somebody’s magnolia has two different types of blooms (one that flowered both yellow and pink comes to mind). It is always escaped root stock and while it may have a certain novelty value, it does not make for a good long-term plant. The root stock – which is commonly grown from seed and only chosen for its strong growth and good root system – on most plants is stronger growing and it will overpower the chosen plant variety in time.

I think this cherry tree may be well past the time when removal of the escaped root stock is an option but, to be honest, when the cultivar isn’t worth growing anyway, this may not matter much in the greater scheme of things. But I recommend that if you ever see strong growths rocketing away from the base of a tree or shrub, it may well indicate that the plant has been budded and it is best to remove escaping root stock when it is young.

Winter in Tikorangi

Finally, because it is indubitably winter here now, being June, I give you a Tikorangi winter. Vireya rhododendron ‘Jiminy Cricket’ in full bloom with a mandarin tree and Braeburn apple. It was this very mandarin tree that convinced me to live in Tikorangi. In my Dunedin childhood, the occasional bag of somewhat green, expensive mandarins was always seen as a treat. Tinned mandarin segments were reserved for decorating the Christmas pavlova. This tree showed riches the likes of which I had never seen before.

 

5 thoughts on “Escaped root stock

  1. Tim Dutton

    We planted a Magnolia ‘Genie’ years ago which struggled for a couple of years and then died back completely to just one small shoot, just below the graft. We had no idea what the rootstock might have been and were going to remove the tree, but the job never got done for one reason or another and next thing we knew we had Magnolia flowers again, but this time in pink and white. It turned out to be M. x soulangeana. Over 10 years later it is doing very well and as an added bonus its flowering overlaps our Magnolia ‘Apollo’ across the driveway and Prunus ‘Awanui’ down the bank the other side of the pond, with all three trees putting on their harmonious display every spring to good effect. A happy accident in this case.

  2. tonytomeo

    Gads! Another of my pet peeves! Weeping flowering cherries were planted as street trees in Salinas many years ago. I needed to inspect them just a few years ago. I was annoyed just to see that some so-called ‘landscape designer’ decided that weeping trees would be a good choice next to roadways. I got even more annoyed to find that most of the trees were mostly replaced by upright growth from below graft unions. They growth was several years, and it occurred to none of the so-called ‘gardeners’, that the suckers should be removed. By the time I got there, I was too late to remove them. The good news is that the upright growth bloomed nicely enough to remain as more appropriate flowering street trees, after the pesky weeping growth of some of the trees was pruned away. Some trees had already lost all of their weeping growth.

    1. Abbie Jury Post author

      We used to sell prunus and too many people want the weeping ones, often under the illusion that they would stay that cute umbrella size with no concept at all of what a mature weeping cherry looks like. Street trees? Madness.

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