I struggle to successfully grow anything but weeds, so I stick to what thrives in my area. If you are pushing the limits, think about what might happen if you get an unusually hot/cold/wet/dry year. Sometimes plants do OK for a while, then you get crazy Weather and they go kerplooey.

Yeah, as a rule I don't stretch zones on woody 'permanent' plants. I do that with herbaceous perennials. And even then, I've started pot growing some of them for longevity, so they can be house grown for the winter for safety and so I get a large full whatever it is.

My zone extenders that I can think of (positive ones): Passiflora 'Incense', Conradinia verticillata (overwinters if protected and winter isn't severe/up and down), sabal minor (seems to be almost rock hardy anyway), salvia greggii (not performing as well as I would like..may let it fade away), crinum lilies (hardy once established due to depth of bulb). My negative zone denial (ie don't like heat) includes some trilliums, winter aconite, crocus (love crocus). There's probably other things that I am going in either direction that I just don't remember now. I don't fuss and experiment as much as I used to. This of course doesn't count things that I know won't make it unprotected (like citrus and pure tropicals).

I do push zones a little bit (ex: I’ll plant a zone 4 in my zone 3), but only for the ones short enough to be covered by snow the entire winter.

I have always pushed hardiness zones! That's half the fun of gardening IMO - experimenting and living on the edge. In fact, I once wrote a blurb about zonal denial for Fine Gardening :-) But the plants mentioned in that article resided in my old garden, which unfortunately has not been maintained by the new owners so doubt they are still alive some 12 years later.

I have never tried a big "push"....its always been plants that are borderline or listed to a zone just one higher than mine. And they are almost always woodies. I usually start with something quite small so if it doesn't make it, I am not out a big investment. And it is never a plant that would be a feature in my garden - that's just putting too much pressure on the plant to perform well and opening the way for disappointment if it doesn't. So I grow them as 'sideline' plants and enjoy them for as long as they survive. Which is often much longer than I'd suspect :-)

Because I currently garden in such a small space and more in containers now than actually in the ground, I haven't been as adventurous recently as in the past......just not enough room. But I do have a coprosma (mirror plant) and an increasingly large grevillea in containers that have lasted at least 5 years and I am currently "testing" various agaves and other succulents for PNW hardiness :-) So far, so good!!

I will say that my climate and current hardiness zone make it somewhat easier for me to experiment (and with more likelihood of success) than it would be for someone living in a substantially colder zone.

GG, as previously bemoaned many times, my major issue these days is with warm weather intermingled with severe cold. It's so unsettled the plants start growth and get zapped, that's my main issue with pushing, to the point that it's just not worth it. I can't even get some hardy perennials a zone or two higher through the winter (if they start early growth).

Would you believe I took severe damage on grape hyacinths this year ? :)

I have planted Anemone De Caen in the fall for spring blooms. They are winter hardy in zones 7 and warmer, I am in zone 6a, close to 6b. Only half of them survived the winter but I believe that is because I have wet clay soil and they are prone to rotting. I have also had Gladiolus come back after forgetting to lift the bulbs in the fall. They are also winter hardy in zones 7 or warmer. Both the Glads and Anemones were planted near the south facing foundation of my house which helps to keep them a bit warmer.

What's interesting is that I have purchased the itea's from local nurseries, although . touch south of me... I am a 30 minute drive from another climate zone.. but I bought the redbud at a nursery north of me. I planted a fothergilla from a local guy and it has done ok.. no dieback... but hasn't grown much. We have 3 redbuds close to where I live growing well. Someone planted a forest pansy 5 minutes from my home.. I am really looking forward to seeing if it survived. Btw, we are in USA zone 5b (Cdn zones are different as my profile state zone 4.

I knew Canadian zones were different but couldn’t remember if they were a bit warmer or colder (along with including other factors besides temperature).

The Fothergilla really likes acid, loose, organic soil, so the higher level of clay and slightly higher pH of your soils vs. mine may be influencing the Fothergilla, or it might just be that they are slow starters. Mine certainly took a couple of years to really get going, though they were just rooted cuttings when planted here.

The generic redbud/Cercis at work has occasional dieback in winter while the Itea is fine, so I imagine that your Itea will be OK since the Cercis are.

The older I get, the less I've been pushing zones. My yard is vast and I don't have the time or energy to coddle things as I once had, there are a few exceptions though. I live in deer country and each autumn must undertake a lot of protecting of shrubs and young trees to prevent them from being severely chomped on or killed by four legged creatures. Now, I'm looking to get a fence installed and if such is accomplished, this would free up time to provide winter protection for a few choice desired plants.

I think the zones indicated for plants is often not accurate. I've tried a lot of Texas natives here in Oklahoma that are listed as zone 8 and they've stood up for years, long enough to know they will tolerate zone 7 quite easily. Its worth trial and error when you do seeds or trades, which is how I started many of them.

Other factors like wet winters as opposed to dry ones seem to determine a plants ability to winter over or not. Good drainage can make a difference and there is also a difference between areas of freeze thaw cycles as compared to places like Colorado where its snow covered all winter. I know that makes a difference for many cactus and other xeric species.

It's interesting how often I read about the deer damage you folks south if us get... We have whitetail deer (I hunt them) but they are far less numerous... My sister lives in GA and as we drive through your states we see dead deer every few miles! Amazing level of carnage... that's a rare sight here and mostly dung the rut..

As long as I can remember (close to a half century!) we've had erratic weather - winters can be very cold then we will get . a big thaw then back to cold. We are pretty much a continental climate. I don't know what impact it will have on my recently planted trees/shrubs, but I am willing to try and see if I can push the limits here there... For instance, I am tempted to try a cornus florida. There's an online nursery that sells plugs for $6... not too much financial risk.. They can be grown successfully close to our Great Lakes as they moderate temps - Niagara falls for instance is Z7 so one could even grow a magnolia grandiflora! They grow cab sauv grapes in the Niagara region too... and that's a 1.5 hour drive from my door (without traffic!)

I would definitely try Cornus florida where you are, particularity if the trees come from a local seed source. I have grown it here, though back when our winters had mmore consistently cold temperatures. It was also common in the band along the south shore of Lake Erie where I grew up. If you are in a particularly windy area, you might want to plant if where it will get some winter protection from prevailing winds, from a belt of trees or a structure.

Chinese dogwood, Cornus kousa, is somewhat more cold hardy than Cornus florida and should be fine in a z5. It blooms somewhat later than florida and is more drought and heat tolerant and has increased disease resistant. And IMO, it tends to be the showier of the two species with larger flower bracts that are produced in abundance.....often to the point where the foliage is obscured by the flowers.

Yes GG, i've considered the KC (milky way is available near me...) - they're slow growing, correct? How big should I expect it to get within 25 years (give or take) in my Z5 - full sun and relatively dryish site?

IME they seem to behave fairly similarly as far as cold hardiness here. I have grown both, and the individual tree’s genetics and siting seem to matter more than species in my yard. I have found they do a bit better with some shelter rather than on a fully exposed site, both C. florida and C. kousa. They grow fine in full sun with adequate moisture, but winter dieback is greater in more exposed sites.

Babs is a much better person to rely on for cold hardiness issues......obviously, that is not a major concern in my area :-) I was just reporting what the literature states in comparison of the two species.

All that aside, I think kousas are just far more attractive trees in form and flower than floridas. Plus they have much greater disease resistance, which is an issue here as dogwood anthracnose is prevalent in this area (affects many of our native western dogwoods, Cornus nuttallii). Not sure how much of a concern that is in Ontario.

In my garden the Kousa blooms longer, starting chartreuse and small and expanding over a couple of weeks to full size. I think I end up with 5-6 weeks of bloom. The leaves are out when the Kousa blooms. The C. florida blooms on leafless branches and my memory is that the blooms last for less time, a bit less than a month. I like them both.

dbarron, After being on this forum for a number of years where it seems most everyone lives up north close to Canada or in the PNW, I think the problem of warm followed by very cold must be more of an issue the further south a person lives. We often get those "false springs" which can be quite extensive that lure us into doing things like trimming back too soon and clearing out around plants only to have a polar front dip down and wipe everything out in a single night, then it warms back up again and the plants have to start all over (no peaches, cherries, apricots etc this year). Those conditions tend to lure (trick) plants into early flowering followed by leafing out with the flowering and fruit trees trees.

Another issue is the number of plants which have no hardiness against heat which is a much bigger issue than cold damage for those living down here. The bigger challenge is getting a plant to survive summer. I've lost a lot more plants to summer than winter. Summer is what prevents me from even attempting to try growing more species of plants than I could list.

I was flabbergasted to read here that Redbuds are an iffy prospect in more northern parts of the country. I just never thought about them as being particularly subject to cold because they grow wild all over the state and we take them for granted since they are as common as dirt. Its one of those trees you plant when you need something that is cast-iron and guaranteed to make it. I appreciate them a bit more now. I planted a Forest Pansy redbud many years ago but the sun is so hot here it looses its purple color in summer and the leaves get burnt looking, blotched, really crinkled and toasted on the edges unless its in shade. I finally took it out because it looked so bad in summer, as if someone had taken a blow torch to it.

Barron asked: "Would you believe I suffered damage on grape hyacinths this year?" Sure I would. Those bulb plants are fine unless they bloom, then they are toast if a front comes through. I've seen it happen to daffodils a number of times when we have a spring-like late January - February.

Hey folks, another Q - I jst found a Cdn source for Kousa seeds (Milky Way). 10 seeds for $5. I've never grown anything from seeds except tomatoes and basil. Is Kousa easy to grow from seed? I figure I can learn over the Internet... could be fun. Then again, I can get a 1 gal for $40

Any seed grown plant won’t be Milky Way, even if the parent is Milky Way due to variability in genetic make up and expression. Just like your kid isn’t you and may be a different height or have a personality more like your spouse or have a different hair color, plants from seed of Milky Way will likely be different from Milky Way in plant size or flower size or autumn foliage color or whatever, though it will also likely have things in common. It’s a crap shoot.

A gallon will save you time (years), and would actually stand a chance of being 'Milky Way', the way no SEED could ever be.

So they market as Milky Way but it’s likely not? Wow.. interesting

Named cultivars cannot be truthfully/ethically propagated by seed. Seed grown trees are just nameless samples of the species....never a specific cultivar. Named cultivars can only be propagated asexually - but cuttings or grafting. At best you would be growing just a Cornus kousa chinensis. But not 'Milky Way'. Always be suspect when you see tree seeds being sold under a cultivar name. They are being offered by an unethical (read "dishonest") vendor.

Seed grown dogwood trees also take a long time to flower...anywhere from 7-15 years. And seeds from pink flowered dogwoods will almost always produce trees that bloom white.

Bamboo muhley was said to be Zone 9 when I first bought it for my Zone 8 home. It is root hardy at 13F . That is all I know. I have had a cool but mild winter and they are not suffering any foliage death at all . So , yes they are happier at Z9 but they do grow in the big Bend and that is a Z8 and Z7. Now I see people saying it is a Z6 plant.Sheesh, Take that with a grain of salt.

I grow LOTS of aloes that are a zone stretcher . I cover the more hardy ones that are in the ground with frost cover and bubble wrap for the REAL BAD fronts. It isa treatment that usually last around 3 days and then they get uncovered.. I also have Russell equisetiformis( Fire cracker Fern). They say it is cold tolerant to 25º. I think the roots are more tolerant but I have killed it before and I still buy it. I have it in a pot on the south side of the house on a stone Patio that gets intense winter sun. I depend on that thermal mass.

Texans do a lot of plant wrapping when the cold fronts come through . Our yards look like a bad garage sale or laundry day with all our old blankets and sheets wrapping the plants. Winter events are short affairs. This year has been easy, cool but warm. 29º . Our normal mininum is 15º. I grew nasturtium outdoors all winter.

I’ve thought about wrapping some of the iffy plants. We don’t get a lot of snow in this part of Ontario. But it can get very cold.

I think wrapping can be a temporary fix. I think its protecting effects might not last for as long as you need it since your cold is so long lasting. The cold will seep through eventually. I am just guessing since I don't know squat about your kind of cold. I imagine mulching with leaves and bales of hay would be better. Ground freeze is still a ground freeze. My sister lives in Alaska and I was telling her that she could extend her vegetable garden with a frost cover and she just laughed at me. The permanent frost comes from below and my frost cover was useless. I just can't wrap my mind around the implications of that. No warming sun either. Here there are tricks to pushing the envelope and they use things that are not necessarily available elsewhere, like Warm sun in the day, thermal masss,.. things like that.

Yep Mara, garden advise is best locally grown. :)

My sister told me the permafrost would expand upwards from below, and sometimes come before the first frost. I think she is pulling my leg (she does that for hoots). What do I know.

Permafrost is tricky!! And it does expand upward from a permanently frozen soil layer that can vary in depth depending on location. But I would have to wonder about how it can move upwards without the benefit of below freezing temps.......that just doesn't seem logical. Maybe your sister is pulling your leg :-)

Alaska itself is a strange place to garden. A short but very intense growing season (with almost 24 hours worth of daylight in summer). And it can have some very mild climate locations as well. I once did a remote landscape design (something I typically avoid) as a favor for a friend of the owner of my local nursery that was in a zone 7!! Who knew??

Actually if it's permanently frozen (aka permafrost), it makes sense as temperatures cool in the air, the frost/frozen will move up. It doesn't require freezing temperatures.

It would take a couple of years to get my head around gardening in Alaska, which I hope to never do.

All Locations along the coast of Alaska are probably quite mild...

I killed so many trees and shrubs trying to push the limits that I think, I'm done with it. These are just to name a few:

Chinese dogwood

Flowering Dogwood Venus

Flowering dogwood Rainbow

Tri-Color Beech

Crimson Queen Japanese Maple

Bloodgood Japanese Maple

Paulownia

Golden Chain Tree

Oakleaf hydrangea

They could be doing just fine for 3-4-5 and more years and then especially hard winter will kill them and this is heartbreaking to see the big tree just die. My Chinese Dogwood lasted for 5 years and then Arctic-cold winter of 2014-2015 killed it.

Interesting... the chinese dogwoods are supposed to be a safe bet in the zone we share, green_go... but 2014 wasn't a Z5 winter.. thanks for input

green_go that resonates with me...I push on smaller plants that are not focal points or key structural elements. To lose those trees after they have been in for a number of years is too upsetting!

Yes, so far that's what I've done, Sara... just the two itea... well, the redbud i suppose could be included.. but they seem to do ok here..

We'll see.. It was -10 F this AM. It's been a cold winter, but not extreme as 2014

my plants that I chance are small. I can cover them with a 30Gallon pot, rip them out of the ground if it becomes brutal.. I would love to grow a Mexican olive )not an olive) but so far I have withstood the temptation that I feel every warm winter. So far so good.

splaker

I have three Eastern Redbud trees (one store-bought, two grown from seeds), all are doing just fine. The oldest tree is probably 7 years old, others are 5 or so....

One of them is planted in the worst location imaginable - on the hill in my backyard, open to all the winds in winter, but all trees are doing great. I noticed that they can have some branches die-back after their first winter, but once established - they are bullet-proof in my garden.

I am similar to greengo. That winter of 14-15 severely damaged but did not kill one of my Kousas. The other is in a spot on a slope and less exposed to sun and wind, and whether due to its site or slightly different genetics (they were both seed grown) it was not damaged. That is what made me realize that I don’t want to grow a tree for 5 or 10 years only to see it half killed. I am willing to try a tree that survives well nearby once, or if I can find a source from particularly hardy stock like the Minnesota strain redbud I have, but I really hate planting most zone 5 rated woodies, even though my area is technically 5a because I know that every few years we have a winter with temperatures that dip below -20.

This was in the Washington Post this morning. We are all going to be looking at plants from different zones, I think!

shifting your gardening perspective

Climate has always changed.. mostly due to solar activity, sometimes due to volcanic activity. I do not anticipate growing palm trees in Canada.

You can grow them now in Vancouver...:-)

Didn't vancouver just have significant snowfall this past winter? This doesn't look like a favourable palm tree growing forcast to me...unless they like -4 lows !! ;)

-4C is not all that cold :-) Certainly not atypical for coastal BC!! Windmill palms, Trachycarpus fortunei, are very cold tolerant as palms go and are routinely planted in this area in USDA zones 7 (-15C) and above (which would include Vancouver BC). In fact, due to the marine presence and sheltered exposure offered by Vancouver Island, there are spots in the Vancouver area (and on the island) that are actually a zone 9.

Mediterranea fan palm, Chamaerops humilis, is hardy to zone 8 and is also frequently planted in this area.

Palm trees in Vancouver BC

We have these palms and more in Z8 Austin . Washingtonia robusta, Bismarkia nobiles, All sorts of palmettos. Even some Fig palms will grow here.,, No coconut or Queen Palms

I do wonder if I should try growing a peony in zone 10b, but I would worry too much if it would just melt! I do like how it looks like a fluffy sandwich cookie but summers are just too much

Try Paonia mascula or p.cambesdessii, Suzanne - both of these Mediterranean beauties are easily (if slowly) grown from seed.

Have grown phoenix canariensis here in east anglia. Unlike the usual advice (plant young and small for ease of establishment), it is best to find the largest specimen affordable for transplanting in an unprotected English winter garden. I started with an 8year old which was already beginning to elongate in the trunk.

Texans don't grow peonies. Maybe in Dallas but not in Austin, San Antonio or points south . I would check with your local guys.