My wisteria has brown through to cream patches on its branches and has a lot of dead branches. Is this a virus? Or could it be dry and need watering?
The patches sound like lichen, which does not kill plants but often attaches to sick plants. I would suspect that a fungus is attacking the plant. Treat the wisteria with a fungicide. I like neem oil myself as it will also kill any pests on the plant. Here is more information on it:
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
My wisteria is in full bloom, it's about 7' high and 6' wide. It is fully covered with blossoms at the moment. My problem is that I'm expecting snow showers tomorrow with a low of about 29. Do I cover the plant? There are beginnings of the leaves starting right now too. I'm afraid the cold will destroy the bush; it's about 20 years old and this is the first year it's ever bloomed full out. Should I cover it with a sheet?
Yes, I would definitely cover the plant. These articles should help as well: https://www.gardeningknowhow.com/plant-problems/environmental/protect-plants-in-freeze.htm
https://www.gardeningknowhow.com/plant-problems/environmental/frost-how-to-protect-your-plants.htm
How do I kill my wisteria? Vines under ground, cant get rid of.
This artilce will help with that: https://www.gardeningknowhow.com/ornamental/vines/wisteria/controlling-or-getting-rid-of-wisteria.htm
When is the best time to plant wisteria seeds, and how many seeds do I plant in one area?
This article will help you:
https://www.gardeningknowhow.com/ornamental/vines/wisteria/grow-wisteria-seeds.htm
Seven years ago I inherited my parent's home. Other family members lived there during these years. They were supposed to take care of the place. They didn't. The wisteria has gone wild. It is encroaching on two neighbors' yards and destroying not only the chain link fence surrounding the property but some of the nearby trees. Articles I have read mention glycophosphate 41% (also known as Roundup or Gly-4) but don't give any dilution ratio. None of the herbicide booklets mention wisteria by name. Can you tell me how much water to mix with how much herbicide to effectively eliminate wisteria, or at least give me a fighting chance?
This article will give suggestions for getting rid of this plant: https://www.gardeningknowhow.com/ornamental/vines/wisteria/controlling-or-getting-rid-of-wisteria.htm
Have just moved into house with a garden. There's a beautiful and well-established wisteria vine, espaliered against a wooden wall. However, the blossoms are not the usual purple or lavender. Instead, they are a dirty white color. Can I change this color by adding something to the soil, as can be done with hydrangea that is pink rather than deep blue?
Unfortunately, there is no way to change the color of the wisteria. Lack of color is normally caused by poor soil nutrition. Have your soil tested and amend it accordingly.
We are moving to a new house and want to take our wisteria with us. It is a vine about three or four years old and the main stalk is maybe three or four inches in diameter. If we cut it back and dig out the root ball, will we succeed or be bitterly disappointed?
Large, well established plants do not transplant well. You will have a 50/50 chance of it surviving. I would recommend instead that you take cuttings or dig out some of the suckers (which are common on wisteria). This article will help: https://www.gardeningknowhow.com/ornamental/vines/wisteria/propagating-wisteria-cuttings.htm