Mike Turner

Your onions likely didn’t form bulbs because they aren’t the right day length cultivars for your area.  Onions come in long, intermediate, and short day cultivars, based on the length of your summer days.  Onions form bulbs in the late spring to early summer in response to the lengthening day length and often go dormant for part of the summer, so your onions won’t be forming bulbs this time of year.  Onions are cool season vegetable and are very cold hardy, but will need to be mulched if you are expecting extended below 0F cold snaps.  

I’m in upstate South Carolina with heavy red clay, hot, humid summers and mild winters.  Blackberries grew fine here , but the first couple of times that I tried raspberries, they didn’t thrive and died off.  Once I added organic matter and built up the fertility of the soil over a period of several years, now the raspberries are thriving to the point of invasiveness.

It should do fine with drastic pruning.  On one winter, mine got killed back to the ground by the cold and it grew back vigorously the following spring.

Native nitrogen fixing trees and shrubs in the Southeast:
Robinia pseudoacacia
Robinia hispida
Robinia viscosa
Gleditsia triacanthos
Gleditsia aquatica
Alnus serrulata
Gymnocladus dioicus

Non-native nitrogen fixing trees and shrubs for the Southeast:
Albizia julibrissin
Albizia kalkora
Albizia coreana
Gleditsia japonica
Gleditsia sinensis
Gymnocladus chinensis
Eleagnus pungens (highly invasive)
Eleagnus umbellata (highly invasive)

Drink bamboo tea.  The bamboo leaves that the tea is made from are high in silica.

Besides those mentioned above, additional winter/spring greens include chickweed, violets, dead nettle, henbit, wild garlic, and stinging nettle.  Then, when the new shoots start growing and the trees start leafing out, there are Smilax and bamboo shoots, and basswood leaves.

Citrus has long been grown indoors in cold climates with short cloudy winter days (think about the orangeries in the palaces in Northern Europe in the 1700’s).  Citrus lends itself to this practice since most cultivars are self-fertile (not requiring pollination), can tolerate low light conditions when dormant, and can be grafted on Flying Dragon rootstock to keep it dwarfed.  

Avocado would be more of a challenge.  They tend to shed leaves when subjected to a change in environment (moved inside after a summer outside), produce a large number of flowers requiring pollination in mid-winter with only a small number of these flowers actually setting fruit, even on trees growing outside in the subtopics.

Both citrus and avocados are grown in Southern California and so can tolerate low humidity,  although spider and citrus mites, if present, can be a problem on plants grown in low humidity.

Pineapples are more adaptable.  They can tolerate low light levels in the winter (at the expense of productivity), are very drought tolerant, have a minimal root system (making them easy to transplant and stuff in a tiny pot ), and in a greenhouse setting will continue to grow slowly and flower in the winter.  I pot up and grow my pineapples in the greenhouse for the winter, then plant them out in my vegetable garden for the summer.  Typically several of them will start flowering in late winter and will mature their fruit that summer in the garden.  They are said to require pollination, but I’ve never had poor fruit set even on plants that bloomed in the greenhouse.

Bamboo shoots can be killed by late frosts just as easily as grass shoots and the shoots of early shooting species of Phyllostachys, like moso (Phyllostachys edulis), can be killed by late frost. Among Phyllostachys, henon bamboo (Phyllostachys nigra henonis) is later shooting then most,  also Semiarundinaria fastuosa shoots very late for a spring shooting bamboo and its shoots are rarely damaged by frost.

Arundinaria appalachiana is a deciduous bamboo.  In the SC mountains, it remains green, despite frosts, into the first week of December, at which time the leaves turn yellow and drop.  Typical height is 4’ with an occasional culm up to 7’.  The appalachiana plants growing in the woods around my parent’s house near Hendersonville, NC tolerated-16 degrees F in 1985 without dying back.