Match the scion and rootstock to the method — cleft, whip-and-tongue or T-budding — and to a window from late winter into spring. In Iran's calcareous and saline soils, the choice of rootstock matters more than the graft itself.
Grafting sets a fruit cultivar on a root that can cope with the soil and water of that particular orchard. In Iran, where a large share of orchards are calcareous, sometimes saline and usually short of water, a graft fails less often because of a crooked knife than because of an unsuitable rootstock or the wrong timing. A healthy scion on a rootstock intolerant of lime produces the very iron chlorosis the grower blames on fertiliser. Before teaching the cut, Farin Kesht Taban asks what the water and soil are and what the orchard's aim is: changing the cultivar, making the row uniform, or saving a damaged trunk. Without that answer, cleft and whip-and-tongue grafts are merely wounds.
Scion, rootstock and three widely used methods
The scion must come from a healthy mother tree, of a defined cultivar, and from mature one-year-old wood; too many flower buds on a weak scion send the energy to flowers rather than to the union. The rootstock needs living bark, a proportionate diameter and an established root system. A cleft graft suits thick stocks and crown conversion in late winter: a vertical split in the head of the stock and the scion cut as a wedge. A whip-and-tongue graft, for two branches of the same diameter, gives more cambium contact and is common in nurseries and in rejuvenating a branch. T-budding, or shield budding, when the bark lifts easily — usually from late spring into early summer with the sap flowing — works excellently on young stocks of pome fruit and some stone fruit. Every method has its time; do not swap T-budding in February onto tight bark for a cleft graft in July on active tissue.
- Cleft: late winter until before full bud break; a thick stock, a wedge-cut scion, and a firm cover against drying.
- Whip-and-tongue: the same dormant window until sap flow starts; diameters close to each other; even wrapping over the cambium contact.
- T-budding: when the bark lifts easily; separate the bud from the wood and set it in the T-shaped cut; after it takes, head the stock back gradually.
Timing in Iran's climates
In the cold regions of Azerbaijan and Shahrekord, do not leave cleft and whip-and-tongue grafting so late that the scion bud opens before the union forms and dies of desiccation; and do not do it so early that a frost separates the graft union. The usual window runs from March into April and shifts from year to year with the snow. In Isfahan and the central belt, it is sometimes possible to start from the middle of February if no severe frost remains. In Kerman, Yazd and Khuzestan, true dormancy is short; finish dormant grafting earlier and do not let T-budding coincide with a heatwave. The day of grafting should be mild: no frost, no dry wind, no July midday. Keep the scion wood in damp cloth and shade; ten minutes of direct sun on the bench kills the bud.
The scion's cambium has to meet the rootstock's cambium, not bark to wood. If the green layers do not sit on one another, the wrapping only preserves appearances.
Choose the rootstock for Iran's lime and salinity
A commercial apple or peach cultivar on a rootstock that goes chlorotic in calcareous soil makes you dependent on iron chelate every spring. For stone fruit on the calcareous soils of central Iran, ask a reputable nursery for rootstocks tolerant of lime and chlorosis, not for volunteer seedlings from beside the orchard. Almond and some hybrids last better in lime than pure peach, but the cultivar's compatibility has to be checked. Pistachio on rootstocks tolerant of salinity and drought is what has kept the orchards of Kerman and Yazd standing; a susceptible rootstock in the same soil empties the tree by the third year. Pomegranate and olive have some flexibility at moderate salinity, but an unnamed seedling is still a risk. In saline soil, a successful graft still dies if the irrigation gathers salt at the collar; buy the rootstock and the irrigation together. Ask the nursery for documentation of the cultivar's identity and the rootstock type. A cheap sapling with no rootstock name is the most expensive purchase an orchard makes.
- Write down the aim of grafting: changing the cultivar, making the planting uniform, or saving the framework.
- Look at the soil and water tests before ordering rootstocks; lime and salinity change the list.
- Match the method to the stock diameter and the sap calendar: cleft and whip-and-tongue in dormancy, T-budding when the bark is ready.
- Keep the tools sharp and clean; tape and grafting wax must protect the union from drying and from rain.
- Once it has taken, remove rootstock suckers and competing branches, and stake it so the wind does not break the union.
Aftercare
Once the union is wrapped, shade and air humidity matter more than spraying water directly on the wound. Do not remove the tape too early, and do not leave it so long that it cuts into the bark; usually, once the union has callused and growth has started, the tape is slit rather than stripped off all at once. Remove the shoots below the union so the rootstock does not smother the cultivar. In the wind of Isfahan and Kerman, use a stake; the graft union is the point of failure. If a cleft graft on a mature tree has several heads, do not convert them all in one year; keep part of the old crown so the roots have food. Regular irrigation and avoiding concentrated nitrogen in the first weeks raise the take rate. The wax or cover over the union must protect against both drying wind and sudden rain.
A good graft has three signs: an even union with no rot, scion growth stronger than the rootstock shoots, and foliage of the intended cultivar without severe chlorosis in that same soil. If it did not take, look at the timing and the cambium contact before condemning the cultivar. If it took and the tree stayed yellow, blame the rootstock and the lime, not the knife. In orchards under renovation, Farkesht grafts onto trees with enough reserves and regular irrigation; a hungry and thirsty tree rejects a graft. In Iran, skill in the hand matters, but choosing a rootstock for calcareous and saline soil matters more. A sharp knife on the wrong rootstock only makes a clean wound.
