I need to prep for winter and have found a variety of ways to do so. Since the "preparing for winter" information online is so diverse for the same plant, I decided to get advice here :-) Bare with me as I have questions about several flowers lol
1) Hosta: Do I cut off leaves now or let the first frost kill them? When I mulch for winter, do I cover the crown area, or just the area around the crown?
2) Dwarf Butterfly Bushes: I have 4 Buddleja Buzz Ivory, do I cut them back now or in Spring? They are about 2 or 3 feet tall and wide. How far back do I cut them? Do I need to add a certain amount of mulch around the base, or is the 1 1/2 inch layer on there now enough for winter?
3) Astilbe: When do I cut the foliage down the the ground...before or after the first frost? Some of my Astible still have some green foliage, and some foliage is yellowing or already brown.
4) Flowering Ginger: I have 3 Indian Surprise Gingers. The foliage has begun to yellow and wilted with the cooler temperature. Do I need to let it die to the ground before removing the leaves & mulching or should I do so now?
5) Alstroemeria: I have 2 Anouska and 2 Eliane. The foliage is green and still growing, however, not flowering. Is there anything I need to do to them to prep them for winter?
6) Lantana: Do I leave it be or do I need to cut it back any before winter?
7. Japanese Painted Fern: Anything special I need to do for it before winter or do I just let it die to the ground? Do I need to mulch over it after it dies to the ground, or when I cut it down?
8) Ruellia Purple Shower (Mexican Petunia): Anything I need to do to it before winter, or do I just leave it alone?
2) During winter, if it hasn't rained, say for 3 weeks, do I need to water them at all?
9) Plumbago Imperial Blue: Should I trim it down or do nothing before winter? Should I wait until spring and do any pruning them?
10) If there is a period of 2 or 3 weeks when there is no rain, do I need to water any of these plants even when it is winter?
Thanks a bunch for answering any of my questions...I am sure I will come up with some more for you all! :-)
My rule of thumb would be if it has green leaves, leave it alone. If it has leaves that have died back and you don't like looking at the dead stuff then you can cut it back, but you don't have to. In general I wait until spring before cutting anything back but on the stuff that dies back to the ground each year it's really a matter of personal preference whether you cut it back or not. Shrubs like butterfly bush that bloom on new growth I would wait until spring.
You didn't ask about this, but something else to remember is that if you have some things that are a little borderline in your zone and they get frostbitten over the winter and some of the foliage dies, leave that dead looking stuff alone until spring (the frost-damaged leaves on the outer edges of the plant can help protect the rest of the plant from further frost damage--otherwise you cut out the damaged stuff, then another frost comes along and damages what's underneath, and before you know it the whole plant is dead)
As far as watering, if you have a dry spell during the winter you may need to water, but it's hard to say if 2 or 3 wks is the right timing or not. It'll depend a lot on how much it had rained before that dry spell (if it had been really rainy for a while first, the ground may be so well soaked that it could go a month or more without needing more), how warm it is during the dry spell, etc. If in doubt, do the finger test (or use a wooden skewer) to see if the ground is still wet several inches down. If it's not then you may need to water, but if it's still wet underneath then there's no need.
I agree with ecrane. Less is more. Most plants survive the weather variations in their zones with very little interference. I prefer not to cut back in the fall so the gardens don't look bare and the birds have something to browse. I'd rather clean up in the spring so new growth looks good and isn't buried by detritus, and to make room for annuals, re-arrange my scheme, etc. I do mulch this time of year, especially newly planted and borderline zone hardy, but try not to bury the crown except on things like roses that like the extra protection- and certainly not on those plants that want good drainage.
As far as water goes, since the plants are dormant or nearly so, and they've eliminated a lot of top growth in preparation for dormancy, they don't need extra unless your area is experiencing an unusual drought. If you can keep your ear to the ground and find out what local experts are saying about the climate in the neighborhood- or county- you will hear if extra dry conditions warrant supplementary irrigation, or any other problem that may come up during winter.