Blueberry varieties - advice (forum)

Heasley starts with ...
Hi, I would like to grow an evergreen or semi-evergreen blueberry hedge in my backyard and would like to know which of your blueberry varieties are best suited to my area.

I live in the Adelaide Hills - mainly cool climate but there are extremes of hot and cold. It is Cold Zone 9a (lowest temp = -6) and Heat Zone 4 (average 30-45 days over 30 degs). Summer average temps are 11-26 while winter av temps are 3-12. The spot where I would like my hedge is in full sun.

The main prob I have is that despite the mainly cool weather, there are always scorching hot dry summer days, and sometimes heatwaves, in Jan-Mar, with sun temps climbing over 37 degs and humidity below 20%. Same as most of southern Aus I suppose. I would like to know which blueberry varieties can best stand up to these extremes of hot and cold in Sthn Aust in full sun, and make a decent hedge. Evergreen or semi-evergreen would be preferred. All other factors (water, acid soil etc) are not a problem.

I have done some research and it seems the Southern Highbush & Rabbiteye varieties are the best, as they are evergreen and heat tolerant, but everything else suggests that my area is NOrthern Highbush type of area due to my very high number of chill hours.

Any advice would be much appreciated. Have enjoyed reading the forum posts to date, but nothing has quite answered this question about heat tolerance of blueberries in mostly cool climates.

Many thanks.

Time: 5th June 2012 12:11am

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About the Author Heasley
Hahndorf, SA
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Lachlann says...
I would guess you could try southern highbush and rabbit-eyes. 37 degrees is not all that high. Mine take 38 degrees without blinking. But they don't like to dry out in the heat so you MUST keep them mulched and well-watered during your summers which I know are very dry. Hot and dry will burn their leaf tips. I don't know how they go with Adelaide water though - they are sensitive to salt. Frost shouldn't be a problem either. I don't know how many degrees exactly they take, but they do come from north America with extremes of climate more than yours. Frost is more likely to affect early blossom than the bushes themselves. Commercially these varieties are grown for early fruit so heavy frosts are a limiting factor for this purpose. In the wild they are understory plants and so get some protection from blazing summer sun.
They are evergreen,unlike the northern highbush, but may drop leaves if they get frosted.
There is a late-bearing Northern highbush variety called 'Legacy' which keeps its leaves during winter.
No doubt you have researched the necessary soil improvement for them. Unless your soil is very acid, they will suffer from iron deficiency which shows up as weak pale new growth. So soil is acidified with sulfur or something else. I also use diluted `no names' vinegar on my plants, which is faster acting than sulfur.
Soil should be aerated with some added coarse sand (despite liking water they are native to sandy soils and can die from fungal root rots if waterlogged), and a mulch which may also help to acidify the soil. They have feeder roots that come right up to the surface. A thick layer of pine bark or pine needles is especially good for these roots. Sulfur acidifies soil by being broken down by bacteria over a long period of time, and needs to be mixed in thoroughly so the sooner you do the soil preparation the better.
You can also expect it to take several years for them to settle in and grow very much - they grow a bit like rose bushes - putting out soft canes one year, which then fill out in the following year. Small amounts of fertilizer will help this along. Do some research as to what fertilizer they like - like other ericaceous plants they have specific likes and dislikes. I use organic material and `earthcore' azaelia and camellia fertilizer. Fertilizers that contain salts or nitrates can burn or kill them.
Prune a bit like a rose bush, cutting out aged ragged canes.

Time: 13th June 2012 6:50pm

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Original Post was last edited: 16th June 2012 12:57am
About the Author Lachlann
south coast nsw
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Heasley says...
Thanks very much Lachlann - this is very comprehensive and I will take your advice into consideration.

Time: 19th June 2012 10:27pm

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About the Author Heasley
Hahndorf, SA
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Posts: 2
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