Please, you might want to warn your customers that they and their neighbors, could be BURIED in ivy within a few years of planting one clump.
In a few more years, nearby and distant woodlands, other wild spaces and yards, may have lost many native and ornamental plants to the unstoppable spread of English ivy.
Up and down the Pacific Coast, and in some states in the southeast, English Ivy is very
invasive. It has taken over my back yard and I'm fighting to keep it from choking out mature pine trees. I had to clear out access to my back faucet recently, along a little sidewalk, and I yanked and threw away a half-cubic-yard of ivy without even making much of a dent in the area over-run by it.
Where I work, English Ivy just rolled right over every other plant, stomping them flat and choking them out. It spreads like kudzu does in the South.
Maybe English Ivy is "no problem" in the other 40 states, I don't know.
But if I were selling kudzu, even very inexpensively, I would say this in large print: "INVASIVE in many regions".
I hope I'm not TOO pushy in bringing this up. I know that some things are horribly invasive thugs in one region, but well-behaved or even hard to grow in other regions.
This site seems to say that 10 states have listed English Ivy as invasive:
" English ivy can invade woodlands, fields and other upland areas and is spread by runners. Seeds can also be spread by birds. It can grow both along the ground, where it can displace native understory species, and in the tree canopy, often covering branches and slowly killing trees."
This site says that:
"English ivy has been reported to be invasive in natural areas in 18 states and the District of Columbia. "
"On the ground, English ivy forms dense and extensive monocultures that exclude native plants. English ivy also serves as a reservoir for Bacterial Leaf Scorch (Xylella fastidiosa), a plant pathogen that is harmful to elms, oaks, maples and other native plants. "
"NOTE: The leaves and berries of English ivy contain the glycoside hederin which could cause toxicosis if ingested. Symptoms include gastrointestinal upset, diarrhea, hyperactivity, breathing difficulty, coma, fever, polydipsia, dilated pupils, muscular weakness, and lack of coordination. This feature also helps ensure effective seed dispersal by birds."
I admit, I never saw any people or pets stumbling around in a feverish, hyperactive coma after a close encounter with ivy. People here are too busy cursing it to eat much of it!
I can tell from our plant database (47 named cultivars) that gardeners SOMEWHERE must like it and plant it deliberately.