Topic: Blueberries

[Jesse]

How big do blueberrie plants get? My book recommends spacing them 5ft apart but I have less space than I thought. Will I get away with 3ft spacing? The varieties are Bluecrop and Herbert.

[Tenuse]

I have exactly the same varieties and I believe that they can get as high as five or possibly six foot tall (don't call them a high-bush variety for nothing!). Mine are one year old and are already 3 foot tall, growing in a 10 inch pot.

Have you thought about putting them in containers as they need very acid soil then you can move them about easily!!

Ten x

[Jesse]

Thanks Tenuse, I've rearranged my planting plans so now I have enough room, 4m x 2m for two plants. I was going to put them straight into the ground because I was concerned that being in pots might restrict their roots and limit the cropping potential. Have you had good cropping from container grown plants or do you think it would be improved if they were in the soil? I have tested my soil and it is neutral so with adding lots of peat and ericacious compost into the planting hole I am hoping to achieve the right level of acidity. I would top up with a thick acidic mulch each year.

[Tenuse]

Jesseveve,

As they are only a year old (not even that - bought as bare-root plants last winter) I was not expecting anything from them this year, but they certainly cropped well for their size. I was considering doing the same as you, putting them in the ground, but they need a PH of about 4 to do well. I'd be interested to see how you get on, I was going to do something very similar (dig a big hole and fill it with ericaceous compost) but wondered what would happen when the roots crept out of the acidic area. They are supposed to do very well in big pots so I will keep them in pots and see how they do.

It is a good idea to net them once they have set fruit as birdies LOVE them even when they are not fully ripe.

You can always take some cuttings so that if for any reason the plants fail in the ground, you have backups in pots! I think you would be ok for a few years - it just depends on how acidic you can keep the ground around them. (Oh and only water them with rainwater!)

Ten x

[Hugh_Jones]

You are most unlikely to get a pH anywhere near as low as 4 simply by using ericaceous compost.  However, if you dig sulphur chips into the soil before planting (or work them into the soil surface if the plants are already in) this will reduce the pH.  An application of 4 ozs per sq. yd will normally reduce the pH by a factor of between 0.5 and 1.0, so you need to check your pH first and then use it accordingly.  The treatment can be repeated as necessary to lower the pH further or to prevent the pH rising again.

However, the treatment will not show any apparent effects on the pH until the soil warms up again, so if you use sulphur chips now wait until next summer before re-checking the pH.

The same treatment is also very effective for blue mophead hydrangeas.

You can buy sulphur chips at any decent garden shop.

[john_miller]

There is such a plant as low bush blueberries (cvs. of Vaccinum angustifolium). They are rated as superior in flavour to the high bush types, being not so highly selected, and are sold for a premium. They need a lot less space than the high bush types and have the added benefit of being ground covers, perhaps under rhodonderons or azaleas? Are these not available in the U.K.?

[Jesse]

Not sure John but my blueberry plants arrived today along with my strawberries and some other things I ordered, it's like christmas here today!  ;D

Thanks for the information about sulphur chips Hugh, will be down to the garden centre tomorrow to get some.

[Tenuse]

Ooh that's interesting about the sulpher chips, we shall have to compare yields jesseveve next year, pots vs. ground!!

Not sure about low-bush blueberries, maybe they are related to bilberries that grow on the heathland? They are very low growing and I think they are related somehow (haven't got my good veggie/fruit book to hand at the moment to check).

Ten x

[Jesse]

Been reading the factsheet from Ken Muir website. It says that blueberries should not be given fertilizers that contain lime or calcium. And they recommend the following per metre square: before planting, 35g superphosphate and 20g sulphate of potash. followed at the end of March with an application of 15g sulphate of ammonia. Each March in the years following broadcast over the soil 15g sulphate of ammonia and 10g sulphate of potash.

Can someone translate this for me please! I planned on taking Hugh's advice and using sulphur chips to get the ph levels right. So really all I want now is a suitable fertilizer. Are these things organic or is there an organic alternative if they aren't. I usually use fish, blood and bone meal but I guess this would be no good because I assume the bone contains calcium. Why the mixture of different applications, is there not just one thing I can use as a general fertilizer?

[john_miller]

They are all different specie in the genus Vaccinum. High bush are V. corybsum, bilberries are V. myrtillus. Low bush blueberries grow on very poor, acidic soils in full sun and, in Maine at least, they can become the sole occupier of large areas of land.
Jesse- you could use dried blood and rock phosphate (I assume that is available in the U.K.?) to reduce the calcium applications. Do you know what your calcium levels are? Blueberries are calcifuges which means they are adapted to grow in acid soils, it does not mean they don't need calcium!
Even this far south of the U.K. blueberries do much better in full sun than shade- I would stay away from trees with them.

[Jesse]

I have planted the blueberries in a huge hole filled with a mixture of ericacious compost, horticultural grit and well rotted horse manure. They are positioned in full sun and sheltered from winds. I plan to test the ph levels in early spring and adjust if necessary using sulphur chips (I believe these are organic). I don't know what the calcium levels are in my soil. It is a clay based soil with no signs of chalk. I was planning on giving a thick mulch of well rotted compost (including leaf mould) mixed with peat (I know, not very enviro friendly) every year and a sprinkle of fish, blood and bone. But when I read the advice on the KM website saying they should not be given fertilizers containing lime (I understand that one) and calcium (don't understand why on this one) and the advice on the mixtures that they should be given then I got confused and thought possibly my initial idea of the peat and manure mulch and FBB would be no good. I'm not striving for perfection and maximum production from them, only so that I don't kill them and perhaps get a punnet or two of berries each year.

[Sarah-b]

Good luck Jess. Do let us know how it all goes.

Sarah,