A. I have interviewed many gardeners and there seems to be only a few hard and fast rules, but for the most part, most agree that you should apply the same manners as you would with anything else - always be polite.
For example, the most widely agreed upon rule is that you should never show up at someone's garden unannounced because visiting takes time away from gardening. You should also never say anything impolite about something that someone grows in his or her garden, such as, "It's just a weed to me" or, "I don't like that plant." One gardener's weed could be another's treasure. You should never make derogatory comments about a plant's condition either.
When making a pilgrimage to someone's garden, you should never trample upon someone's plantings or shrubs. You may take seeds if you ask permission first and accept if they are offered to you. If you don't care to have the seeds, accept anyway and pass them on to another gardener who may be interested in them.
When making a pilgrimage to a public garden, the same rules apply with one more addition: do not dig up or pick plants from public parks or gardens, especially plants that are indigenous to the area. Not only is it improper to do so, you may also be subject to fines! Here in Texas it is very illegal to pick bluebonnets along the freeway and the authorities are stringent in adhering to those rules. Besides, if everyone picked them, there would be none left to enjoy!
The only "rule" which there seems to be some discrepancy about for gardeners is basically a tradition that you should not say "thank you" for cuttings or plants. The superstition holds that the plant will not grow or will die if you thank the giving party. Some die-hard traditional gardeners still hold to this tradition and politely say something like, "I'll take care of it for you until it blooms." The less traditional gardeners believe that it is an old wives' tale best forgotten.
Another tradition is that you should not ask someone for cuttings from their garden but wait until it is offered, but most gardeners will tell you that they are flattered if someone asks them for a cutting and most are usually willing to share. I interviewed one gentleman who said that he would dig up a perennial for a stranger. Of course, it is up to you as to how you would "thank" him! A good rule of thumb that works in all cases-give something from your garden in return.