I have planted in the ground thyme, mint and oregano. Will they survive the winter in the ground? If not, what can I do to protect the plants?
All of these plants should do well in the ground overwinter. You don't have to do anything special to them.
If the mint is one of the "specialty" varieties, you may want to take some cuttings (2-3" pieces off the end of a runner) and root it in water inside. After it's rooted, stick it in a small pot and grow it on over the winter. Though most mints are hardy to the point of being indestructable, there are some (like "pineapple") that are iffy in Z6.
Yes they will. They thyme should stay up, while the mint and oregano will die back to the roots. Though Martie's right, it doesn't hurt to root cuttings from each and winter them indoors as insurance the first year.
Mulching the garden at the first frost isn't a bad idea to protect the roots can help in an especially cold climate/winter, and in the spring, you'll want to clean up the previous year's dead growth from the mint, and the oregano especially (just don't tug against resistance, lest you rip out the roots; snip rather than tug). And make sure the mint and oregano don't spread beyond where you want them to, because they WILL take over the whole garden if you let them. Otherwise, all three are fairly trouble-free plants.
All of my mint and thyme varieties suvive up here in NH in zone 5 as does regular, Greek oregano. The thymes are evergreen and can be picked all winter, if I dig them out of the snow, but the mints and the oregano die back. Less hardy oreganos, like Syrian, Cretan and Italian, I keep in pots and bring in before first frost. I don't mulch, per se, but I don't remove accumulated fallen tree leaves until the spring.
i have inherited an herb garden with oregano that has been overgrown two years and is very leggy and unattractive. is it possible to dig up and "roll" the roots of the plant into a more compact shape, or just push the entire plant further into the ground. i am a new gardener, and dont know if these roots can be disturbed, especially this late in the growing season.
In my Z6, I have never seen thyme come back, although years ago, my dad had mint that seemed to return. Its all gone now, due to many years of tilling and weed barriers. Oregano was one he never grew, but I suspect that if you have some protected area that you want to keep herbs in as permanent plants, it may do well. When I grow these now, I start from seeds and plant them after the frost have gone. All are planted in the same location where the previous years were, and none have every sowed any signs of older plants returning. They are all located adjacent to my small greenhouse.
I used to think that thyme did not come back. I was not being patient. Thyme takes a little longer to green up in spring than other bushy herbs do. Don't pull the plant because you think it is dead! Water it regularly, have faith, and it will eventually sprout new leaves.
Oregano can be cut back, but not too severely. Oregano can be a lovely bush. Oregano can be divided to produce more plants. Mexican sage is often used as oregano. True oregano is called Oreganum vulgare.
While some people use a few Vulgare oregano in salads it is in much less demand because it lacks flavor. The only way I could kill a 10 year old 10x20' mat of it was to place a sheet of clear plastic over it for a few weeks. I still can't plant anything in the area as it is a solid root mass. Greek Oregano is the better flavored one.
My mint is spreading its boundaries each year in much the same fashion as the oregano. Thyme, however, is more prone to winter injury. I lost my thyme bed last year, the first winter that I didn't protect it from winter winds with hoops and row cover.
For "candace_grower" with the leggy oregano:
Regular clipping on your oregano (as well as with mints, lemon balm, and so on) will make for a bushier plant. While you can trim it back now, it is late in the growing season so I'm not sure how bushy it will get for you. Next year be sure to keep it pinched or clipped on a regular basis to the size you want. You'll be surprised how bushy and attractive your plant will be plus you'll have herb for kitchen use. I'd suggest this course of action over any fiddling with the roots.