Horridculture – Multi-Grafts

P91116+++Bare root fruit trees will be available in about a month. It is probably my favorite time of year for going to nurseries. (Since I grow just about everything I want from bits of landscape debris, I do not often go to retail nurseries.) It is also rather frustrating to see what sorts of bare root material are popular nowadays, and what sorts are not. Horticulture has gotten so ridiculous!

Most of the formerly common cultivars of fruit trees that I remember are no longer available. They were common for a reason. They perform well here. Retailers used to select cultivars for their respective regions, instead of pimping out weird new but unproven cultivars, or just taking the same faddish cultivars that get sent to other stores within a vast chain of big box stores.

One of the weirdest of fads are multi-grafted fruit trees and roses.

Multi-grafts are certainly not new technology. Back when horticulture was taken more seriously, fruit trees for home gardens (which might be the only ones of their kind in their respective gardens) were sometimes, if needed, outfitted with a secondary scion of a pollinating cultivar. The pollinator could be pruned low and subordinated, as long as it bloomed with a few flowers.

Most of us preferred to simply plant two separate trees that could pollinate each other. If one was less desirable than the other, it was just maintained as a smaller tree so that it would not occupy so much space that could be utilized by more desirable types. Each tree had its own uncrowded area. If one succumbed to disease, it did not necessarily affect those associated with it.

Multi-graft trees are not so easy. If the trunk of a multi-graft pear tree gets infested with fire blight, all the scions grafted to it succumb. Because almost no one prunes them properly, the most vigorous cultivars dominate and crowd the less vigorous. Even well pruned trees are always asymmetrical because each cultivar exhibits a different growth rate and branch structure.

Multi-graft rose standards (trees) just look weird and freakishly unnatural. Pruning must ensure that one cultivar does not crowd out the other, just like for fruit trees. The multi-graft rose in the picture above was planted with three others just like it. Two of them crowded out one of their two scions. It would have been easier to simply plant two in white and two in burgundy.

Multi-graft plants are useful only if ground space is very limited, but air space is not. For example, such a tree planted in a hole in a deck can extend limbs over the deck where other trees can not live. If maintained properly and separately, each part can produce its share of fruit in season. I once did this with a pear tree that was espaliered on a fence over a concrete driveway.

Winter Is Bare Root Season

80124thumbWhile dormant for winter, some types of plants get dug from the soil and sent to nurseries as ‘bare root’ stock. Some get packaged with their otherwise bare roots contained in bags of damp sawdust. Most just get heeled into damp sand in the retail nurseries where they get sold. These simply get pulled from the sand when sold.

At their new home gardens, bare root plants simply get planted where they will sleep through the rest of winter. In spring, they wake up and start to grow as if nothing ever happened. How sneaky! They do not need big holes for their bare roots. Their graft unions (the ‘kinks’ at the bases of the trunks of grafted plants) must stand above grade. Roots only need to be spread out laterally.

Soil amendment should be minimal. Too much soil amendment promotes root growth around the trunk, which can inhibit root dispersion elsewhere. Too much excavation and amendment below the roots may eventually settle, so that graft unions sag below grade, and get buried. A light dose of fertilizer a bit later promotes early root growth, even while the branches are still bare.

Bare root plants are much more portable than canned (potted) plants. Several can be wrapped and sent home in a small car, or even through the mail; which is why so many bare root plants can be purchased online. (Climate zones should be considered when purchasing online.) Because they occupy less space than canned plants, many more varieties are available in nurseries.

Because they are so easy to handle and process, bare root plants cost about a third of what canned plants cost. Mail order plants from growers often cost even less than those that must be sent to retail nurseries first. Bare root plants are at least as reliable as canned stock, disperse roots more efficiently, and are less likely to be infected with disease when they arrive.

The most popular bare root plants are roses, cane berries, grapevines and fruit trees, like apricot, peach, nectarine, cherry, plum, prune, almond, apple, pear and persimmon. Flowering crabapple, flowering cherry, poplar, lilac, forsythia, wisteria, rhubarb, strawberry and asparagus are also available.

Bare Root Stock Has Advantages

31225thumbAnyone who has had undergone surgery knows the advantages of unconsciousness. Any frat boy who woke up after a night of overly indulgent inebriation, with his face adorned with objectionable graffiti, knows the disadvantages. A lot can happen while one is unaware that it is happening. This is exactly why so many bare root plants become available while they are dormant through winter.

Bare root plants get dug and deprived of the soil that their roots grew in, leaving the roots bare. Some get their roots packaged into bags of damp sawdust. Others get their roots heeled into bins of damp sand in retail nurseries. Roots are only bagged or heeled in to stay fresh. They get pulled from their sand or separated from their bag of sawdust when ultimately planted into the garden.

It might seem violent, but it all happens while the plants are dormant and unaware of what is happening. They go to sleep happily rooted into the ground wherever they grew, and then wake up in a home garden somewhere else. It only takes a short while to get reoriented before they develop new foliage and new roots as if nothing ever happened. The whole process is surprisingly efficient.

Canned (potted) plants are actually less efficient in some ways. They are bulkier and therefore more difficult to bring home from the nursery. Their confined roots are more likely to be disfigured or binding. (Roots that wrap around the inside of a can will constrict on themselves as they grow.) The media (potting soil) could contain disease. Worst of all, canned stock is much more expensive.

Bare root plants are remarkably easy to plant. Their planting holes only need to be big enough to contain the roots. Soil amendment should be minimal. If too much amendment is added, or holes are too deep, new plants are likely to sink. Graft unions (the distinctive ‘kinks’ just above the roots) of grafted trees must remain above grade. Roots should be spread out laterally and downward.

Smaller bare root plants like cane berries, grapevines, gooseberry and currant are already moving into nurseries where Christmas trees are relinquishing their space. Fruit trees like apricot, cherry, plum, prune, peach, nectarine, almond, apple, pear, quince, fig, pomegranate and persimmon will arrive next, followed by blueberry and roses. Poplar, flowering cherry, flowering crabapple, forsythia, lilac, wisteria, rhubarb, strawberry and asparagus might also be available.