I was reading a response in the NAFEX "Richard Moyer and others is that for Zone 6/7, it is not the absolute winter minimum that kills kakis, but late spring freezes after the trees have broken dormancy. The great Easter Freeze of 2007 killed 10 out of 12 'cold hardy' kaki cultivars I had, most of them 4-8 inches in diameter. The two that survived unscathed are 'Hira Tanenashi' and 'Sung Hui', only because neither had broken dormancy. We ate and sold many fruits from these two trees this fall, until Christmas. Three nights of +19, 24 and 27F killed the other 10 'cold hardy' cultivars to the ground. In themountains of Korea, I observed huge, old kaki trees at Buddhist temples. So it's "not always how cold it gets, but how/when it get's cold", especially for some of these Asian plants we try to grow in the eastern US. Cliff England, at Nut Tree nursery in KY, also is trialing cold hardy kakis. Some of his material from northern Japan and north Korea". So Tony, can I protect the hardy Asian persimmons wtih your method for short period from a late freeze in early April? Others comments are welcome. Thx.

Yuccas do not die after flowering. And they will provide a very similar effect to the phormium without the hassle of necessary winter protection. But you will not get the intensity and variety of foliage color with a yucca. Cordyline is a very commonly found plant sold as a summer annual that could substitute (i.e. 'Red Sensation') and tends to be far less pricey than the flax. Phormium, N.Z. flax, is not a houseplant but a tender perennial that is sold widely as a landscape plant in warmer zones (8+). They can get huge (6-7' tall and equally as wide, depending on cultivar). They are becoming more frequent in colder zones as a seasonal container plant. When moved indoors, they are very prone to mealy bugs, so watch for that if you bring indoors to overwinter.

Mike, there is a very sharp line running roughly down the middle of 6b in the east. Warmer than that, HTs aren't too bad. Colder than that, they become much harder very quickly. I know a lot of people south of that line that exaggerate how cold they are because they are about the coldest people they know growing HTs. There are also microclimates - mostly urban heat islands, that make some people think they are much colder than they really are. That's a very common phenomenon around here. The people who are succeeding with HTs all, coincidentally, have small, urban yards. Otherwise, if you truly know people who are having good success growing HTs in an eastern zone 5/6, do everything you possibly can to get them giving advice. I'm involved with the big HT garden in Hyde Park, Vanderbilt, and we will be rethinking what we are planting because of the cost of replacements. We really should be purchasing about 400-500 new roses a year, and that's just silly money. If I can get enough ramblers and polyanthas into that garden so the HT count is around 500, everything becomes somewhat manageable. Montgomery Place has given up on their rose garden because of the cost. Kykuit, which is far enough south to grow HTs, has given up on them because of disease issues. Spraying in public spaces is problematic. It's only a matter of time before the state considers outlawing it. BTW, I'm plugged into the ARS network. Once you make climatic (temperature) adjustments, nobody is really doing much better than we are.

I'm in zone 5 Ottawa,Canada. Zone 4 for you in the US. They used to say you couldn't grow J.maples around here. But for 20 years I always could, and have never lost any, except 2 variegated ones. I have about 25 varieties, a sort of J. maple forest in my back yard & I am running out of room. Good thing they are dwarf trees, unlike our native maples that grow to 50 ft. I wholesale them from (grown in)BC, zone 7-8. They do not loose hardiness by grafting and propagating in a milder climate. The hardiness is built into the plant. I will say that they can sometimes be slow to establish, and this is the important part. Any tree should be planted early and well cared for in the first season, so it is well established going into it's first winter. I don't believe in bare root trees doing well, too slow to establish, or over wintering in a pot. They should always be planted in the ground and well mulched. I do think they prefer a more acidic soil. Ours is neutral approx. 6-7ph, so I spread sulphur everywhere every couple of years to acidify a little.(I don't like pink hydrangeas, prefer blue) I saw a study once, out of U of Michigan I think, where when they tested plants, and they found that plants growing in acidic soil seemed a little hardier than the same plants growing in more alkaline soils. In the past I have used geo-textile fleece as a winter cover for the first few winters, but snow makes a great insulator as well. I get a bit of tip dieback sometimes, but it doesn't matter since they grow back very well, as if they were pruned. There is a sort of wilt going around in J. maples lately, others have noticed as well. It doesn't hurt the tree, it just attacks some of the newest growing tips as they are finished flushing out in summer....sort of self pruning. We regularly get to minus 22 celcius (-10 far.)here most winters, with minimal problems. Even with last winter, the worst in 20 yrs., there were no losses. The only damage I ever notice is the heavy snow pack in spring, will sometimes crack the weeping types as it weighs them down and melts. Variegated types do seem less hardy, possibly due to the fact that variegation is a mutation and therefore weaker. Red and green types are perfectly hardy. They all seem hardier as they get older. thanks, Rich