Multigrafts, double-grafts, ‘family’ trees, fruit salad trees, cocktail trees – there’s lots of different names for them, but they’re essentially all the same thing. Fruit trees with different varieties or cultivars grafted onto the same rootstock.
If the different grafts are all the same variety (e.g., all apples), they will normally be sold as multigrafts, whereas a ‘fruit salad tree’ describes a tree that has different types of fruit from the same family, e.g., apricots and plums.
Generally speaking, fruits from the same family can be grafted onto the same rootstock, e.g., plums and apricots are compatible, peaches and nectarines, and pears and quinces. However, due to the magic of grafting, other combinations may also be compatible, e.g., some varieties of peaches and nectarines are compatible with plum rootstocks, allowing for glorious combinations of 4 fruit types on the same tree. While it’s safer to stick to known compatibilities, it’s always worth experimenting with odd and unusual combinations, because apart from your time, there’s absolutely minimal cost involved.
One of the best ways to think about a multigraft is as a work of art that you are constantly reviewing and improving. A famous examples of this is the ‘Tree of 40 Fruits’ Series by New York artist Sam Aken.
Many of the problems that can happen with multigrafts (see the list below) are avoidable or fixable by paying careful attention to graft placement and detailed pruning, and then by reviewing and responding to how the tree has actually grown and performed each season.
If you think of your tree as a living work of art (rather than the ‘plant and forget’ model that most gardeners use), and have high expectations of what you want to achieve with the tree, it’s possible to make them incredibly productive.
If you’re prepared to put the work into them, there are lots of benefits of having these trees in your garden, one of the most important being that they allow you to increase your food security in a small space.
How does that work? The more biodiversity that you can stack into your garden, the more you’ll be protecting your food supply from the many disasters and natural events that can ruin a crop. If you’re growing 10 varieties of apple, rather than just one, then if a hail storm comes along or you get a particular disease outbreak, chances are that some varieties will fare better than others, which reduces your chances of total wipeout.
The more varieties you can play with in the garden, the more you can work towards a consistent, even harvest throughout the entire growing season, rather than the normal cycle of glut and scarcity that most home fruit growers have to deal with.
Other benefits of growing multigrafts include
- increasing food production in a small space
- practising your grafting skills
- making the most of an existing tree with an established root system, rather than having to get a new tree established
- Inappropriate varieties – not all varieties grow as well as each other in a given locations, so there’s a risk that some varieties you choose to graft won’t thrive, but, so what? Just regraft with another variety.
- Pruning. It’s a very common scenario that some varieties will be more dominant than others, either because they are more compatible with the rootstock, the graft was better quality, or the variety is happier in the location. This can make it more difficult to train the tree into a balanced shape and the dominant branches can end up being bigger and more vigorous. This needs careful management with pruning to prevent the problem becoming worse by allowing the dominant side to crowd out or shade the slower-growing varieties.
- Branch positioning. It is important that the grafted branches are evenly spaced along the main trunk to produce a balanced form in the mature tree and to avoid undesirable crowding. On a single-variety tree, a misplaced branch can simply be pruned off to allow well-placed branches to grow. However, pruning off any of the first branches of a multigraft tree means sacrificing one of the varieties.
- Providing pollination partners is one of the main reasons for creating multigrafts, but unless varieties are carefully chosen with this goal specifically in mind, it doesn’t always work. The varieties need to not only be compatible, but also flower simultaneously. In order for all varieties on a multigrafted tree to be pollinated, they must be carefully selected for flowering times to overlap sufficiently. Again, this problem, should it occur, is very fixable by regrafting with a more suitable variety.
- Different varieties can be vulnerable to different pests and diseases. In the worst-case scenario, the introduction of disease by one variety on a multigrafted tree can compromise the health of the entire tree, particularly if you accidentally introduce a virus to the tree by using infected grafting wood. This is offset to a large degree by the advantages of increasing biodiversity (see above), but it’s good practise to only ever use grafting wood from trees with no visible signs of ill-health, and ideally a good record of productivity as well.
- Labelling. This almost seems too frivolous to include in this list, but it’s probably one of the problems we hear about most regularly, for all fruit trees, not just multigrafts. It is hard to find a good labelling system that can easily withstand the ravages of time and the weather and remain not only in place but also readable! Our solution is to take a four-pronged approach:
- make effective, permanent, low-cost labels by cutting up aluminium cans into labels, and using a nail to etch the name into the metal. Punch a hole in the label and use a piece of wire to attach it to the tree. Don’t attach it too tightly around the branch or it’s easy to strangle the branch as it grows.
- Check the labels at least once a year. Make sure they’re still in place and still readable, and loosen the wire if necessary.
- Keep a paper (or computerised) record of the location of each tree, its variety, and any varieties you add by grafting.
- Take photos to back up the computerised record.
Multigraft fruit trees take a bit more work and diligence than single-variety trees, but the benefits are huge, not just in terms of increased production, but through providing other environmental services to your garden, providing beautiful sculptural trees, and providing a life-long interest and passion.
But be warned – it’s addictive!