September 3, 2016

1 - Fruit trees cannot be successfully grafted to Siberian elms, though I wish they could.

2 - Lime trees and most citrus cannot survive outside in New Mexico in the winter.

Yard and Garden September 3, 2016

Q.

Can I graft a fruit tree branch onto a Siberian elm root stock?

- Lee G.

A.

I like the way you think. As readily as the Siberian elm grows in our soil and climate, it would be wonderful if we could turn them into fruit bearing trees. Alas, even though the idea is great, the science works against us. The scion (variety that is grafted onto the rootstock) must be compatible with the rootstock.

Siberian elms are not graft compatible with fruit trees. It will not be possible for you to graft apple, pear, plum, cherry, or any other fruit to the elm. Neither can you graft nuts such as pecan or walnut to the elm root stock.

As I read your question my mind went back to a report of a laboratory in which alfalfa was grafted to sunflower. These should not be graft compatible, but in a laboratory setting it was accomplished successfully. Generally, plants must be closely related, in the same species or genus to be compatible for grafting. Sunflowers and alfalfa are not even in the same plant family, so they should not be compatible for grafting. Some members of the genus Prunus (cherries, plums, almonds, etc.) will not graft to other plants within the genus Prunus, and they are more closely related than alfalfa and sunflowers. So, the topic of which plant can be grafted to which other plant can be complicated, but fruit will not (outside a laboratory) be successfully grafted to elm rootstocks.

I still like the way you think. Continue being creative. And if you decide to try it and it does work, I really want to know. Science says it will fail.

Q.

This question probably comes up every year at this time, but I need information on how to protect my lime tree. I planted it planted 6 months ago. Information regarding how to protect it would be helpful for the "winter" months. I have seen various suggestions, but I would appreciate your advice.

- Jack C.

A.

I am assuming that you are gardening in Southern New Mexico since that is the only part of the state with any chance of growing citrus. I discussed your question with Jeff Anderson, NMSU Extension Service County Agent in Dona Ana County. He told me that there are some Mandarin orange varieties that may survive the winter in warmer microclimates in Southern New Mexico, but the lime tree is tropical and cannot survive the winter anywhere in New Mexico.

With a lime tree (and most other citrus such as oranges, grapefruit, and lemons) you will need to overwinter the plants indoors in an atrium or other sunny, non-freezing location. That means you should dig up your lime tree and put it in a pot if it is to have any chance of surviving in New Mexico.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

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