Rootstocks

Wurzel-stock, m. rootstock, rhizome, -stoff, m. (Old Chem.) radical principle, -werk, n. root system, -zeichen, n. radical sign. 

In both studies the apples were grown in the biodynamic orchard Boomgaard ter Linde in the south-western part of the Netherlands. We used full grown apple trees of the Dutch variety Elstar on dwarf rootstock M9,2460 trees/ha, grown on limey humus sea loam with trickle irrigation. The experiment was replicated four times. 

Conservative is used to define orchard and management factors that once introduced cannot, or are extremely difficult to, change or require substantial additional investment to do so. Among these are soil and other site-specific conditions, choice of variety/cultivar and rootstock, planting density and tree canopy formation, system stabilisation measures at orchard set-up and installations to buffer extreme events. 

The choice of rootstocks was until recently thought to primarily affect the growth and vigour of the tree and to only have a minor effect on intrinsic fruit quality. However, recent research has shown that, under low input organic production practice, the choice of rootstock can have a significant influence on tree fitness and tree nutrient acquisition, and thereby also on fruit quality (Weibel et al., 2006a). 

Weibel, F.P., Ladner, J., Monney, P. and Sutter, F. (2006a). Improved organic and low-input apple production by weed competition tolerant rootstocks , Acta Horticulturae (.ISHS), Submitted Sept. 2006. 

Gilreath JP, Motis TN, Santos BM, Noling JW, Locascio SJ, Chellemi DO (2005) Resurgence of soilbome pests in double-cropped cucumber after application of methyl bromide chemical alternatives and solarization in tomato. Hort Technology 15 797-801 Gokte N, Mathur VK (1995) Eradication of root-knot nematodes from grapevine rootstocks by thermal therapy. Nematologica 41 269-271... 

Gupta AK, Khosla K (2007) Integration of soil solarization and potential native antagonist for the management of crown gall on cherry rootstock colt. Scientia Horticulturae 112 51-57. doi 10.1016/j.scienta.2006.12.004... 

The nematode problem in citrus is very different from the problem in vegetables and other annuals, where the soil can be fumigated between crops. The final solution of this problem will require either a resistant rootstock or a treatment which will tip the balance in favor of the tree. This latter might be either a systemic which will move downward in the tree and make the roots either poisonous or distasteful to nematodes or a soil treatment which will penetrate to great depths and destroy the nematodes without seriously injuring the trees. Either type of control is a big order. Standard known rootstocks are all attacked and an entirely new rootstock might require 25 years to test thoroughly, while in the chemical field there is no precedent in other crops. 

Salviafrigida Boiss., perennial herb with a thick woody rootstock. Stems sohtary or several, erect, 10-30 (-50) cm, below pilose to villous with sessile glands, densely glandular above with capitate glands. Leaves mostly basal, variable, ovate to narrowly oblong, 2-12 x 1.2-5 cm. 

Control of weeds in fruit is just as important as for vegetables—except where fruit trees are growing on vigorous rootstocks. A full-sized fruit tree surrounded by a wildflower meadow gains many benefits from it, and together this association forms a valuable wildlife habitat. But in the case of small trees and all soft fruits, weeds compete with the crop plants for light, water, and nutrients if very profuse, they can reduce air flow and increase the likelihood of fungal attack. Do not let weeds get out of hand. 

Apples grow best n rich, free-draining soil with a pH of 6.5. If your soil is less fertile, you can compensate, not only by your soil treatment, but also by using a more vigorous rootstock or even growing the tree on its own roots. Choose an open site in full sun but protected from the wind. Avoid frost pockets. 

Over many centuries apples have been selected and bred to suit a very wide range of situations. There are now cultivars to suit warm and cool climates (Zones 3-9) with rootstocks to match. 

Like most fruit trees, apples are not grown on their own roots. Instead, they are grafted onto the roots of compatible trees, usually other apples. Rootstocks help to control the eventual size of the tree. Depending on the rootstock selected, the same cultivar of apple might grow 8 ft (2.5 m) or 30 ft (9 m) tall. Ask the nursery for advice on heights and rootstocks. 

Espaliered apple Just as climbers flower better when their shoots are trained horizontally, so apple espaliers can bear fine crops. With a vigorous rootstock, the tree can be trained with as many tiers of branches as space and inclination permit, but three, or perhaps four, is the norm. 

They are usually trained with three tiers of branches, at 18-in (45-cm) intervals. For a three-tier espalier, erect a post and wire support structure with wires at 2,3V2, and 5 ft (60,110, and 150 cm). Planting distances will depend on which rootstock the tree has been grafted on. 

For general advice, see Apples (p.294). Most European plums will set some fruit without cross-pollination, but nearly all will yield better when cross-pollinated by another European cultivar. Japanese plums must be cross-pollinated by either a Japanese or American type. American plums also need cross-pollination for best yields. Rootstock choice can further influence your plum trees success. Ask a specialty fruit nursery for help in selecting a suitable combination of trees on appropriate rootstocks. 

Gil-Izquierdo, A. et al.. Effect of the rootstock and interstock grafted in lemon tree (Citrus limon (L.) Burm.) on the flavonoid content of lemon juice, J. Agric. Food Chem., 52, 324, 2004. 

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