TREES, PLEASE! Graft Smart - Don’t Grift
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By Robin Y. Rivet, for Let’s Talk Plants! April 2026.
Graft Smart - Don’t Grift
Grafting is not mysterious.
Like other forms of plant propagation, success requires knowledge of biology and a bit of practice. However, when a sharp knife cuts through the vascular cambium – a tree is definitely not happy to be wounded.
Similar to what occurs when people are injured, a tree initially attempts a “self-repair” process. If both the rootstock and scion vascular cambium layers align, callus tissue will try to seal the laceration, ideally stimulating re-growth. If closure succeeds, the vascular region may re-connect, then differentiates to grow new xylem and phloem cells that will restore water and nutrient transport throughout the plant. If callus growth fails, necrosis usually sets in.
During a dormant season (when grafting is typically performed), the cambium layer may be only a few cells wide, so if alignment is not near-perfect, the new cultivar (or branch) may never completely callus over, and could rapidly decline. Plus, the vascular cambium is not perfectly linear - so “healing” is complex. Check out this micrograph of a sunflower stem’s vascular region. Read more about CODIT.
Loss of Phenotype Plasticity
A potential peril of commercial agricultural grafting is that the scion of cultivars is usually cloned. The DNA of the resulting trees are at risk for replicative failure since we know that repeated cloning can degrade DNA, although cloning from genetic material is likely here to stay. The bottom line is the science is in its infancy. Many fruits we consume today were once spontaneous genetic mutations from seedlings. You can still experiment with growing seeds.
When is grafting illegal?
It is illegal to graft trees and bypass regulations created to prevent the spread of diseases. HLB arrived in California because a resident in Los Angeles ostensibly imported and bud-grafted a tainted piece of scion from a diseased Florida citrus tree, and the rest is very sad history. If you do graft citrus, ONLY USE VIRUS FREE STOCK! Citrus tristeza virus was an example of serious devastation wrought by cloning. In the 1970’s most all Meyer’s lemon trees were discovered to be carrying this lethal virus, and as a result - millions of lemon trees had to be culled to stop the spread. Meyer’s Improved lemon is the result of that vulnerability, and now virus-free budwood is required for all citrus grafting.
Guerilla Grafting is banned.
Although it might seem odd, there have been instances of people illegally grafting fruiting wood scion onto fruitless municipal trees. This is considered a crime in most US cities. Guerilla grafting is usually banned despite the good intentions of skilled grafters. Fortunately, some cities have begun to allow planting fruit trees on parkways – if residents care for them.
Don’t Graft Scion from Patented Species.
Descriptions – PPAF, PP, USPP, PVP, PVPA, PVR, TR
Active plant patents legally prevent reproduction of cultivars - by any method. And, not all illegal tree propagation involves grafting. Propagating plants can be as easy as breaking off a piece of live wood and sticking it into soil - sometimes dipped into rooting hormones to boost success. If patented, that’s illegal cloning. There are definitely cautions. I’ve reproduced my own pomegranates similarly, but most are very old cultivars. I once grew a wonderful soft-seeded pomegranate called ‘Smith’, but its patent expired in 2023. However, Smith soon acquired the trademarked name ‘™Angel Red’ - which licensed the name commercially, and prohibits reproduction for resale under that moniker. When I rooted my own Smith cuttings to give away, they were distributed freely as ‘Robin’s Red’. The question is, how to verify if a plant in question is still protected by a patent? For this article, I found it very difficult to find one verifiable source that listed all active plant patents.
I found many patent lists, but none were comprehensive, and most are not up-to-date or are limited in scope.
· This is a US gov’t. site: https://www.uspto.gov/patents/basics
· USDA – patent descriptions: https://www.ams.usda.gov/services/plant-variety-protection
· USDA: https://apps.ams.usda.gov/CMS/
· Google has a useful site, if you want to look up a PP#: https://patents.google.com
· Fruit and Nut database: https://www.fruitandnutlist.org
· Maryland library: https://digital.lib.umd.edu/plantpatents
· University of New Hampshire: https://ipmall.info/content/plant-patent-directory-legislation-and-articles-interest
· Proprietary: https://www.plantsnouveau.com/industry/plant-patents
· Proprietary: https://www.provenwinners.com/patents
· Trademark manager: https://markwatchplants.com
Most plant patents don’t exclude growing seeds from a patented plant, but some utility patents do. Species like eucalyptus trees are almost exclusively propagated by seed, and that may be a key to their value as a natural resource - since their DNA has natural phenotype plasticity; hence their resilience.
