There doesn’t seem to be a lot of consolidated community info on fuzzy kiwi growing, especially for zone pushing. Kiwi has only been grown as a major commercial crop outside of China for 60-70 years, so there hasn’t been a great deal of info trickling down to hobbyists. Much of this info comes from forum posts of @scottfsmith, @kiwinut, @vkelman, and others over the years. The basic care of fuzzy kiwi isn’t different from hardy kiwi. There are plenty of extension booklets on kiwi production that cover trellising, pruning, etc. Most fuzzy kiwi are Actinidia deliciosa, but Actinidia chinensis (yellow kiwi) is similarly suitable and may be slightly hardier.
Most, if not all, fuzzy kiwi can handle temperatures of at least 10F (zone 8) and usually to 0F (zone 7). This means fuzzy kiwi can be grown in most of zone 7 and probably 6b if sheltered. I have seen massive fuzzy kiwis at Longwood Gardens and Morris Arboretum, which are 6b/7a. Morris Arboretum collected theirs from China in the 80s according to their accession log. Longwood Gardens rates their A. chinensis, sourced from Logee’s in the early 80s, to zone 4. I have seen this one covered in fruit.
The biggest challenge to hardiness isn’t necessarily the cold, but temperature fluctuations causing sap to flow too early. A freeze can then cause damage to trunks and potentially kill the vine. Painting vines white may help, as well as planting in sheltered locations and along south facing walls. Another issue is vines waking up too early and being damaged by heavy frost/freeze. Most fuzzy kiwis have low chilling requirements and may break dormancy too early. This will result in the loss of theyears crop as well as potential damage to the vines. Young plants are more sensitive to cold winters, similar to pushing zones with figs. Getting plants thru the first couple years may be difficult but cold tolerance should increase with time. Avoid locations prone to late/early frost.
Hardiness aside, the length of the growing season is a limiting factor for fuzzy kiwi growers. The main commercial kiwi, Hayward, needs 225-240 frost free days. Saanichton is the primary variety recommended for shorter seasons/colder climates. It is claimed to be around 5 degrees hardier and matures several weeks earlier. It was developed in Canada for use on Vancouver Island. Saanichton should do well thru zone 6b/7a on both sides of the US. Multiple growers in Maryland (around 190-200 frost free days) report it handling temperatures of 0F or lower without issue and cropping most years.
Other possibilities include:
Blake - earlier ripening date than Saanichton and purports to be partially self fertile.
Bruno - similar ripening date to Saanichton, low chilling requirements may be a problem
Exbury - from England, similar in season to Saanichton but has much smaller fruit.
Elmwood - slightly later than Saanichton, low chilling requirements may be a problem
Jenny - self fertile and zone 7 hardy. Relatively new?
Good results have been reported with ElDorado (partner with male Early Bird, yellow/green A. chinensis), Soreli (yellow variety from Italy), HongYang (red variety from China) but these do not appear to be commercially available.
ARS-GRIN has some fuzzy kiwi (deliciosa and chinensis) from Soviet Union, China, and Japan that probably warrant some testing in colder climates. I believe scion importation is no longer allowed to prevent disease from entering the US.
All kiwi are dioecious, having male and female flowers on seperate plants. As with hardy kiwi, some fuzzy varieties can set fruit in the absence of a male (Blake, Jenny), but males will improve yields. Bloom times between males and females must match up, as some bloom earlier than others. Green blooms later than yellow (A. deliciosa vs A. chinensis). It seems that hardy can pollinate fuzzy and vice versa, but usually fuzzy blooms earlier than hardy. Best to have a male for each species to avoid disappointment. Pollen can be stored or purchased to hand pollinate in a pinch.
Commercially, kiwi is harvested around 5.6-6.5 brix, then refrigerated to finish ripening (acids break down and sugars increase). In colder climates let them hang as long as possible before hard freeze (25F? 20F?) then store until ripe. If season length isn’t a limiting factor, dark colored seeds are also an indicator of maturity aside from brix. Once picked, they need to be stored in a fridge or root cellar to allow sugars to develop, and can be stored for 3 to 6 months under optimum conditions. From Edible Landscaping “It is a winter food, with a continuous supply of ripening fruit starting in November and continuing through the months of December, January, and February. Other fruits ripening at that time of year are Arkansas Black apple, Russian pomegranate, hard and soft persimmons. All of these fruits go well together for fruit salads and dishes for festive occasions.”
If anyone has further experience to share, please do!