If this is an ok question.... I like to bring my patio planters in (sunny plant room, not a hot house) )for the winter filled with annuals that I try trim and to winter over. BUT I have a terrible time with whiteflies as the days grow longer. What are some of your solutions? Also which plants have you had success keeping alive till spring? Thanks for any help, Trish
This time of year the days are getting shorter. Don't expect to overwinter annuals. They are not designed to survive the winter months. White flies thrive if plants are kept too dry. Try misting the plants with plain water every couple of days. Also there is sticky yellow flypaper you can get to get rid of whiteflies. Look for it in the garden section of where you bought the plants.
Yes, you can overwinter certain annuals. I have had the same Geraniums for years, as well as a Cortyline which started out less then a foot, and is now 4' or more. Other annuals you can over-winter are, Tradescantia pallida 'Purple Heart' petunias Bouganvilla Coleus Impatiens, and there are probably few more. You might try neem oil for whiteflies.
Technically, you cannot overwinter annuals, because by definition they only last one season. Many tender tropical perennials are grown as annual plantings in northern gardens. These plants can be overwintered indoors or are sometimes kept in a dormant/semidormant state in a cool basement or garage. This will depend on what plants we are talking about here. The plants so far listed can be overwintered, but marigolds or cosmos will not make it to another season.
The plants listed by Bluewing are actually tender perennials or shrubs not annuals. They are often sold as annuals because they flower the first year from seed or have attractive foliage. Most Petunia cultivars are annuals but hybrids of the perennial species are now sold also. Cordyline australis is actually a tender shrub that is sold as seeding plants for the foliage. Bouganvilla are actually woody vines. The "Coleus" of the horticultural trade are actually cultivars of Plectranthus scutellarioides, a tender perennial. The "Geranium" of the horticultural trade are actually hybrids involving a number of shrubby species of Pelargonium.
You should try spraying them either with an organic insecticide, or making it into a "dip". Fill a bucket with water and the insecticide and turn your plantsupside down into it. Make sure not to spray or dip in full sun otherwise the plants can burn, and rinse off the mix after about 20 mins, some plants don't like to have anything on there leaves. Another good way is to cut back the plants very hard, this way they can keep growing all winter, and you will have cut off some of the infected parts of the plants. As for plants that will survive, only non true annuals will survive, you cna find info on which plants are true annuals online. Just search for them and it should give you this info. I have good luck with keeping geraniums,pelegoniums,inpatiens,newgiunea impatiens,amaranthus,coleus,heliotropes,bush daisies,african daisy,ostespermum,begonias,dahlias,cannas. Those sorts of things, hope this helps you out.