Are multigraft fruit trees a good idea?

Have you heard of the “Tree of 40 Fruit” project? It’s an art project created by American artist Sam Van Aken, where he creates beautiful mega-multigrafted trees, for example a peach tree with more than 40 different varieties of peach and nectarine, for their aesthetic value. They are absolutely stunning (we can’t show you one here because we didn’t get permission to use his photos, but here’s the link to his website if you want to have a look).

multiple-trunk-different-colours-helena-smallInstead, here’s a photo of a multigraft tree from a recent garden consultation we did, showing the different coloured leaves of the two different varieties on the same tree.

 

Not as spectacular as having 40 different varieties putting on their various autumn colours, but you get the idea! Here’s another one of a multigrafted cherry showing the different coloured blossoms in spring (this photo is from Wikimedia Commons).

A multigraft is, as the name suggests, a tree that has multiple varieties grafted onto a single rootstock. So for example an apple tree with Pink Lady, Granny Smith and Fuji all on the same tree (which coincidentally, is one of the trees we have for sale this year). Multigrafts are always the same type of fruit (e.g., all apples), whereas a tree with different types of fruit on the same rootstock –  say a plum, an apricot and a peach – is called a “fruit salad” tree and is quite a different animal.

The idea of a many-grafted fruit tree is not new – there are a couple of very famous examples around the world, such as this ‘family tree’ that has been grown by Paul Barnett in West Sussex, England, on which he’s grafted 250 different apple varieties (photo from the Daily Mail).

Paul Barnett with apple tree

Multigrafting has been used not only as a repository of genetic material of lots of different varieties, but also as a mark of the skill of the master grafter, proving not only their grafting skills, but also their superior pruning and management skills in keeping each separate variety alive and growing, and keeping the whole tree in balance.

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A multigraft plum tree in the garden of one of our Grow Great Fruit program members

Which  brings us neatly to the question of, should you bother?, because while multigrafts have lots of advantages, they are almost always a harder tree to manage in the garden, if you’re trying to keep the different varieties in balance with each other, and they can be daunting for a new gardener in particular.

Sometimes keeping the tree in balance doesn’t matter, for example if you’ve grafted a piece of wood of the same fruit but a different variety to act as a cross-polliniser on to your tree because it wasn’t setting a good crop of fruit. In trees like that, you’re not aiming to grow both varieties in equal proportion.

But if you’ve planted a multigraft because (for example) you have limited space but still want roughly equal amounts of an early and a late apple, then for sure it matters – there’s not a lot of point of having a multigraft Gala and Pink Lady if you get 10 boxes of Gala early in the season (when you already have plenty of plums and peaches), and then have to wait until the end of the season when you pick 2 Pink Ladys from one weakling branch!

So, how do you manage them?

The trick is to pay a lot of attention to your pruning in the first few years of the tree’s life (which we call the ‘establishment phase’). Monitor closely how well the different varieties are growing, and you may need to prune the more dominant variety back quite hard at the beginning to let the weaker side get equally established.

Of course, one of the pruning principles is that the harder you prune, the harder your tree is likely to grow, so the tree’s most likely response to hard pruning is that the dominant side will respond with even more gusto. You can minimse this bounce-back effect by pruning the tree in late summer, rather than winter.

Another trick that might help if you don’t want to continually prune is to weigh the dominant limbs down more horizontally (e.g., with a brick) so the height of the growth tip is lower than the height of the weaker side of the tree. This physical height confers an advantage onto the weaker side, and the tree is more likely to direct more energy and resources to the weaker (higher tip) limb, allowing it to catch up.

So is it worth it? Absolutely! If you’re interested in gardening and growing fruit, all of this is tremendous fun, both the grafting and pruning management. It can be a quick way to experience the age-old relationship between farmer and nature (“who’s in charge here?”), that often starts as a battle for new growers but can end with a much deeper understanding and respect for how nature works. And remember, the tussle goes on mostly in your mind – the tree will just keep being a tree.

 

What should my fruit trees look like in spring?

As new fruit growers get to know their fruit trees, they’re often unsure what’s ‘normal’ in the different seasons – that was certainly the case for us as we learned our trade! Gradually we’ve learned by experience what to look for at different seasons to tell us what’s going on in the trees and the soil, so we know whether we’re on the right track. This year, it looks like we are!

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This heritage Goldmine nectarine is showing excellent growth in early spring.

We’re pretty happy with how all our orchards are looking at the moment. Our farm was pretty knocked about by the drought (like so many others) and the flood that followed, which led to a number of disease issues and even some tree deaths.

But this year the orchards are looking vital and healthy, and any trees that have experienced problems in the last couple of years are recovering well.

Most trees have a good crop, and even better, have put out good spring growth, which is one the main signs we look for to tell us that the tree is happy and the soil is doing its job.

What to look for

If you’re looking at your fruit tree and wondering if it’s looking the way it should, firstly look at the leaves – they should be big, a bright green colour (though the growing tips will often be orange, red or pink), and nice and shiny, like the healthy looking leaves on this plum tree.plum-leaves-healthy

This early in the season there shouldn’t been too many holes or blemishes on the leaves (though they often accumulate a lot of damage by the end of summer) and they should be looking pretty sparkly.

Depending on where you live, the flowering will have finished on most fruit trees, and you should be able to see small fruit forming, like this Bramley apple tree.

bramley-flower-apple

The other main thing to look for early in spring is whether any of the leaf buds are starting to extend into new shoots. The ability of the tree to grow this new wood each year is key to the ongoing health of the tree. Here’s a few examples of new shoots on different types of fruit trees:

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New shoot on peach tree
plum-tree-growing-tips
The numerous orange growing tips on this healthy young plum tree show how healthy it is.
growth-pear-tree
A vigorous 30cm new shoot on a pear tree.

Crop load

Mid to late spring is also the time when you start to get an idea of how much fruit your trees will bear this year (we call this the ‘crop load’). Here’s how our trees are looking at the moment.

Apples

Most varieties have set a good crop, the only exception being Golden Delicious. Gala are quite light, but will still pick a lot more than last year. Gravensteins, Bramley, Cox’s Orange Pippin, Snow, Fuji, Pink Lady, Granny Smith and Jonathon all look good. Having lost most of the apples and pears to birds the last two years, the key to our success this year will be to get our newly acquired netting out over the trees and secured nice and early in the season.

Apricots

Most varieties have a medium to heavy crop, though Castlebrite were very light in one block (see below). In the house block where we have two rows of most vareities, our pruning strategy last year was to cut one row back hard to start bringing the height down. As we expected, the row that was pruned hard has much less fruit on it (through a combination of losing fruit buds to the hard pruning, and shocking the trees into growth as opposed to fruit production). However we’re happy to see that the heavily pruned trees are responding well with growth throughout the tree, not just at the tops of the trees.

Pears

Nearly every variety has set a good crop, though both Josephines and Nashi are on the light side. Trees have responded really well to the harsh pruning we gave them this winter, putting out a lot of their new growth nice and low in the tree where we want it, rather than up high where it prevents us netting the trees!

Peaches and nectarines

Our new orchard (planted in 2010) will pick a healthy crop this year, which means all of the 18 varieties of peaches, and 7 varieties of nectarines we grow should be well represented at markets. Several of these (for example Wiggins, Peacherine, Stark Earliglo and Redhaven)  haven’t yet yielded a marketable crop from these 3 or 4 year old trees, so we’re really looking forward to getting to know them.

Plums

Nearly every variety of plum has a good crop this year, the only exception being the European plums (President and Angelina) in the Plum Block. Luckily the Angelina trees in another orchard have set heavily, so we’ll still have plenty to sell over summer. We’re particularly happy to see most of the trees in the Plum Block, which are carrying phytophthora as well as other fungal diseases, are growing really well, and have large, shiny green leaves. Again, this is a really good indication to us that the soil is doing what it should, and has an active soil microbe network that is providing the right conditions for the tree to grow well. We’re also happy to see varieties like Amber Jewel, Satsuma and Ruby Blood all carrying strong crops, as each of these varieties has been a shy-bearer over the last couple of years.

Cherries

Our only disaster so far this year (we’d be completely shocked if there wasn’t one!) is the massive losses in the 90 cherry trees we planted in the new cherry block. We planted the bulk of the block last year, and most trees are growing well, but about two thirds of the the three new rows we planted this year have died. Having ruled out all the obvious things like the trees getting too dry, a problem in the soil, rootstocks, the trees drying out when planted etc etc, we’ve narrowed it down to a dodgy smelling fish emulsion we added to the dipping water we used to innoculate the roots of the trees when we planted them. It’s a pity we can’t prove this theory one way or the other, it’s much easier to learn from our mistakes when we can categorically establish what the mistake was!

Pests and diseases

Some of the main pests and diseases might already have made their presence felt. Here’s a few things we’ve noticed…

Aphids

We’ve seen a minor aphid outbreak in the peaches – really just a few odd limbs here and there, not enough to cause much damage, and just enough to attract the many predators that will clear this pest up for us.

aphids and predators
aphids and predators

Phytophthora

This root rot disease took hold in a lot of our peach and nectarine trees after the flood, and we lost many trees and a lot of limbs. This winter we pruned out all the dead wood, and we’re happy to see most trees that have shown sypmptoms in the past have started the season well and are putting on new growth – an excellent sign that the ‘good’ fungi in the soil are thriving and outcompeting the phytophthora.  We’ve still had a little dieback, and some trees are so badly damaged that even though they’re trying valiantly to recover, we may have to pull them out and start again in that spot with a different type of tree.

Earwigs

There’s already quite a bit of earwig damage in the nectarines, which led to a rapid change of plan to temporarily abandon the thinning and scramble to get all the banding of the trees finished to keep the earwigs out of the trees. They’re an easy pest to prevent, as long as the banding is done early enough before they’ve already taken up residence. Next year we’ll be changing our routine to get the banding done much earlier, before we even start thinning. We’ve also made a modification this year to do the banding much higher in the tree, of individual limbs rather than around the trunk. This will help to prevent earwigs getting at the fruit by using the grass to bypass the tape.

Blossom blight

The House block experienced moderate blossom blight in some varieties this year, despite looking early in the season as if there was none! Rainy conditions at the wrong time led to this minor outbreak, which reduced the size of the crop in the Castlebrite. Luckily our other main apricot orchard had almost no blossom blight (thank heavens yet again for microclimates!!), and between the two orchards we have a good crop of every variety including Castlebrite.

So there you have it, the 2014/15 season spring update! Hope your fruit trees are bringing you lots of joy.