various questions

1. I have three outside hibiscus plants. One is Luna Series and is still blooming; the other two are the same, but I'm not sure what they are. They are tall and have never bloomed. I only purchased them this summer. Should any of them be cut back and how much?
2. Is lantana hardy in zone 6. I have two that were absolutely beautiful in hanging baskets and I was wondering if I could plant them in the ground to come back next spring
3. I have three french lace weigela that are growing wild. They are about six feet tall and still have blooms on the very top. When should they be cut and should I cut them to the ground?
4. Tropical hibiscus that was outside all summer. I have brought it in and have placed it in a sunny room. There are no blooms right now, but is not losing leaves. Should this just be left as is or do I need to do something more
5. What type of care do red star spikes (Cordyline) need as houseplants? Are they hardy in zone 6?

1. Your Luna hibiscus are herbaceous and will die back over the winter, then resprout from the ground next year. If it's still blooming I'd leave it alone for now and enjoy it as long as possible. Once it dies back it's up to you whether to cut back or not--they are rather late to emerge in the spring so if you leave this year's branches in place you won't forget where the plants are and accidentally dig them up next year before they've decided to come up (I've heard some people say it's as late as June before they start to grow again)

2. Lantana is not hardy in zone 6.

3. With Weigela, I think you're supposed to prune it right after it's done blooming (early summer). This late 2nd bloom doesn't count, if you cut it back too much now you won't have as many flowers next year. But if they're severely overgrown and you care more about getting them back in shape vs having a ton of blooms then you could do some pruning now. I'm not sure if they're one of the shrubs that responds well to being cut all the way down--hopefully someone else will know. Don't do it unless someone tells you it's OK--some shrubs respond great to this, but some won't come back so definitely make sure it's one that responds well before you do it. The other option for plants that don't respond well to being cut all the way back is to take out 1/3 of the branches now, then next year do another 1/3, then the following year do 1/3, that way you do get the growth back under control without being too stressful for the plant.

4. Sounds like your hibiscus is fine, just watch out for bugs and make sure you water properly. If it's happy where it is, it may give you some blooms over the winter but don't worry if it doesn't.

5. I can't think of any cordylines that would even be remotely close to hardy in zone 6, so definitely bring them in for the winter. I've never grown them indoors so hopefully someone else can tell you what conditions they enjoy indoors.

the corylines need bright light and some warmth. They do very well indoors. I grow them in a greenhouse at school and we abuse that poor thing. It can take quite a licking and keep on ticking ( i just had to say that). If the leaves turn yellow just cut them off, it's one of my most favorite plants and No it won't grow in the winter in your area or mine TN.