winterising and some questions

winterising and some questions

today was a balmy 84 but it is getting cooler. in north texas we've hit lows in the 40s but nothing devastating. a lot of plants are potted and im wondering if i should just move them into the house/garage - and we've got a lot of plants. last winter the garage looked like a green house - or let them sit out the winter. most them are going to need to be repotted or will be put in the ground next year (they were potted because i was hoping to be able to live in my own space this coming spring and dont want to "waste" them on someone else's yard.) specifically - butterfly bush - info ive read online says to cut way back in the winter and cover with mulch but that's for colder sections of the country. if it's protected from frost by being in the garage, i should be able to let it be, right? hydrangeas - plenty of folk have these in the ground around here. if i leave it outside, how much, if any, will i have to cut it back - these were just bought this spring and still on the small side? the house im in doesnt have a lot of good direct/full sun places for plants - should i just give up on my herbs? ive got mint, oregano, rosemary, basil, stevia and lavender. the annuals im just interested in seeing how long a life i can get out of them. there are three separate "groves" of banana trees in the backyard and every year they come back in greater number (it felt really good to take a whack at them the other day). besides having to dig out the roots (which are under lava stones) is there anything i can do to minimise their reoccurence next spring? also, im probably jumping the gun big time here, but if i wanted to start plants from seeds, when is a good time to plant them (indoors, obviously) to be ready to go into the ground in the spring. im in texas and spring can come pretty early.
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