What plants have you found thriving well outside of the USDA zones they're "supposed" to inhabit? Was it because of a microclimate, unusual weather, or other factors - or do you think the zone rating is just wrong?
I ask because I have often used the zone ratings to determine what I might be able to plant - but there may be plants I've ruled out that actually could thrive here (zone 5).
There's a lot of traditionally tropical plants that survive here if they have well established roots. After a year or two where they are covered during hard frosts, they can be safely allowed to freeze all the way to the ground. The plants that regrow from the roots never get as big as their tropical cousins, but they are mainstays of local landscaping.
If I were experimenting with this, I would start with plants that can survive hard pruning. At the end of the growing season (after they went dormant) I would prune them as small as necessary to cover for the winter, though the least pruning the best. After one or two winters like this, I would let nature take it's course.
Thick mulches and microclimates can also play a big part. This winter we're going to experiment with keeping a tropical flower potted on our porch through all but true freezes. I think the protection of the roof and extra heat escaping from the house will keep it alive until spring.
Many plants that are supposed to thrive in my zone die a horrible death here or have to be planted at a drastically different time of year to make it. Yet, many plants that absolutely won't grow here ever, never, ever in the history and future of the universe for all time as a god given fact it's impossible to grow them here - they grow just fine for me.
In my garden, the temperature isn't so important as the rainfall. That and daylight sensitivity seem to be my main restrictions on what will grow.
If I want to grow it, I buy some seeds from a few different sources, plant a small amount as a trial (holding back about half the seed in case it grows like stink and I want to grow it again).
The books say zone 9 for water chestnuts, but they have overwintered with no problems through several zone 7 winters in 2 foot high, 3 foot diameter tubs sitting on the ground. I've also had water hyacinth survive several 10 degree F winters in the working pond in my vegetable garden, in the spring, tiny plants start appearing in the floating mush left over from the winter's frost/ice.
Location: Western Massachusetts (USDA zone 5a, heating zone 5, 40"+)
Hablitizia Tamnoide... They struggle but don't produce anything.
Location: Upstate SC
posted 3 years ago
Comfrey, dandelion, and common plantain struggle to survive in my climate and soils and have to be coddled in order to survive. The combination of cecil sandy loam. limited summer rainfall, and high 90's summer temps makes it a challenge growing plants that aren't heat or drought tolerant.
Most of the USDA Zone information is pretty outdated(pre warming trend so from around the 1960's).
The things to look for are average temperatures, first and last frost dates, hours of sunlight, intensity of sunlight.
for example, in Arkansas there has been a fairly significant increase in UV intensity from 30 years ago, this has caused some problems for things like blueberries, peaches, some apples.
Corn used to not do so well here but now it fries half way through growth for the most part.
sun lovers are liking afternoon shade now, or their leaves get sunburn. tomatoes are about the only plants that still love full sun all day.
I am doing lots of observation now, the last three years I started doing a trend chart and it is showing that we are indeed in a horticultural changing time.
Interestingly, my people have said this is the time of the 5th shaking of the earth, many wonder if we will make it through this period.
What I am seeing is changes due to normal shifts, some can be shown to have happened many times over the last few hundred and thousand years.
Use the Zones as a guide but not as a bible, Observe and keep notes about what plants do in your gardens, that will help in the years to come.
I've had success with trees that aren't supposed to do well here and I've had failures of trees that used to do great here.
we tried corn for the first time this year and it didn't form ears.
I'm not sure why, but for next year we are discussing trying three or four different varieties to see if we can find one that will work for us.
one thing this years corn did do was help the squash we grew it with so it was not a loss in our eyes.
next year we will have more garden beds ready and one or two will be dedicated to our companion plantings of squash and peppers.
The beans we grow are so prolific they would smother the corn so we don't plant a traditional 3 sisters.
Mimosa trees. They grow like weeds here,despite being outside their zone.
Can't kill the damned thingsby cutting them back,but they hate to be transplanted.
I had a huge one in the back yard that caught some disease and "died".
So we have cut it down to some high stumps,only to find it regrowing.
Not that I mind.
On the should grow here but won't,apple trees hate me.
Or rather, they seem to be a magnet for pests and diseases,making them hardly worth planting.
Truthfully, that only seems to apply to the ones bought at a store.
For example there is a bush shaped apple tree that lives down the street,in front of an apartment building.
Totally ignored by the residents and management,the apples are small, green,tasty, and mostly pest free.
That tree and I are going to make some beautiful babies together,via air rooting.