Like all citrus, limes can reproduce sexually. This means that male pollen from citrus flowers--that tree’s pollen or another’s--fertilizes a flower’s ovary to produce a seed that can grow into a mature plant. Key limes grow “true” to the characteristics of parent trees when grown from seed, but this is not generally true of other limes--or other types of citrus trees. So most limes are propagated commercially through grafting, which produces clones, or genetically identical plants.
Grafting is the preferred propagation practice for citrus trees because in a given growing region only a few citrus varieties have roots that successfully resist typical diseases and pests. Yet other trees produce more and better fruit. Because any variety or species of citrus can be successfully grafted onto any other type of citrus--limes and lemons onto orange trees, for example--citrus trees are usually created this way, which allows the most desirable fruit to be grown on the strongest rootstock.
Lime seeds can easily be grown as trees, but with the exception of key limes it’s hard to know what you’ll get. To grow limes from seed, pluck seeds from fruit, wash them, and then plant seed 1/4 inch deep in a sterile planting medium. Speed a seedling tree’s maturity by using it as budwood--to graft as buds onto other rootstock--when it’s as big around as a pencil.
Layering and Cuttings
It’s also possible to propagate a new lime or other citrus tree through layering on larger branches, though this approach is useful only if you’ll be satisfied with a tree growing on its own root system. You can also take cuttings of green wood from smaller branches and root them as new trees, with the same limitation.
The process of budding, a specialized form of grafting, involves skillfully grafting young, green, budded wood onto desired rootstock. Budding allows desired types of limes or other citrus fruit to be grafted onto the most advantageous rootstock for a given growing region, greatly enhancing plant success. Collect budwood from a lime tree’s second-to-last growth flush.
The grafting adaptability of citrus trees makes it possible to customize one or more citrus trees by “top-working” them, an intriguing home gardening project. Create a multi-variety lime tree--one with all the fruit needed for cocktails--by budding branches of different limes onto a lemon, orange or grapefruit tree. Or combine limes with lemons and oranges on one tree. Thriving rootstock is the key.
Commercial growers want predictability in the fruit they produce--Satsuma mandarins should taste just like every other Satsumas, because fruit lovers expect that--so taking a “let’s see what we get” approach has little value. But curiosity rather than crop demands can be a guiding principle for home gardeners with adequate space. Growing lime trees from seed is a worthy challenge, though it may take 10 years for that tree to bear fruit and the experiment to end.
- University of Arizona Extension: Budding Citrus Trees
- Texas A&M University Extension: Home Fruit Production: Citrus
- University of Florida IFAS Extension: Key Lime Pie Tree
- Ultimatecitrus.com: What Varieties of Citrus will Grow True from Seed?
- University of Florida IFAS Extension: Citrus Propagation For Homeowners
- lime? image by tomcat2170 from Fotolia.com