Blackcurrants

I've had 2 blackcurrant bushes for several years and have yet to get more than 6 or so berries in total! They flower heavily but very few of them set. The bushes are healthy and neighbouring redcurrant bushes produce copious amounts of fruit (provided i keep the aphids at bay).
Has anyone out there any suggestions before I dig them up?
Graham
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I have two species & three varieties of currants, though not the black currant per se. Two of mine fruit well, & the the third didn't fruit at all for two years but this year fruited a little. The one that has fruited poorly is the earliest in blossom, so it's primary problem is there aren't enough bees up & around that early in the year, although it is also a highly ornamental cultivar & some shrubs developed for maximum flower don't necessarily have maximum fruiting to follow.
Although currants are by and large self-pollinating (with bees' assistance), SOME cross-pollinating would even so be helpful. With blueberries, having two compatible cultivars would be absolutely necessary to get good crops; it's not regarded as essential for currants. Yet according to a study by J. B. Free in the 1960s, & studies since, cross-pollination between distinct but compatible black currant cultivars increases fruit numbers & size. Black currant will even cross-pollinate with other Ribes species, such as gooseberries.
Occasionally bees specialize in certain plants and bypass others, so it's best to have more than one kind of bee in your garden; honey bees are not picky & even when they do show preferences, black currant is one of those preferences. But unless someone is keeping honeybee hives in your neighborhood you'll be reliant on sundry other species of bumblebees & leafcutter bees & mason bees &c, & you may have to introduce mason bees in a timely way yourself. If you do any poison spraying for insect control, probably you'll never have a sufficient bee population, but if you are organic about it, you can attract more types of bees to the vicinity by planting flowering perennials that bloom just before & while the currants are blossoming. If you notice any underground hives on the property, avoid disrupting them so the bees feel safe & happy & stick around. I lost a bee hive when I reduced the area that some lavender covered; they didn't like me shoveling near their hole, & I was very sorry that they shortly after moved out.
Black currants produce the majority of their fruit on one-year-old wood that grows from two to three year old wood. So bad pruning technique could be removing buds, though if you're getting good flowering this wouldn't be an issue. Removing wood older than three years will concentrate more vigor in the young fruiting limbs. (Unlike black currants, my red currants produce fruit on older wood.)
A final consideration is the amount of sunlight a black currant gets. Black currants is an understory shrub, so likes at least a LITTLE shade. If the shrubs are extremely exposed & the blossoms are cooked at the hottest point of the day, it may keep them from setting fruit even if bees do get to them properly.
Also, if you're on a windy hill, bees will not work in an area while the wind is blowing. Planting a leeside hedge or having a wooden fence as a wind break will make it more inviting to pollinate. Our place is on a hillside & the first two years it was hard to attract enough bees, but we put in a number of substantial-sized young trees, & now even in high winds our gardens are pretty calm. That & the increasing number of flowering shrubs & perennials means we have PLENTY of bees, though I still fret we don't get enough EARLY bees for early blooming shrubs.
So the main thing is to increase your garden's population of bees, without whose assistance black currants never fruit well. Set up mason bee hotels on all sides of the house, but especially in proximity of the shrubs you need pollinated, as mason bees are short-flight bees (unlike honeybees that can range for miles) and might not travel even so far as from one side of the house to the other. With our modern world so full of toxins, even if you don't use insecticides, your neighbors' use of garden chemicals could be lowering the pollinator population to next to nothing, & many gardeners discover there is no part of the year when the number of bees is sufficient to do a good job. I fortunately live among organic-gardening neighbors, so we've got several species of bees up the wazoo, & this year we're even being visited by lots of honeybees though I've not a clue where they're coming from, I don't see any box hives anywhere in the neighborhood.
-paghat the ratgirl
--
"Of what are you afraid, my child?" inquired the kindly teacher.
"Oh, sir! The flowers, they are wild," replied the timid creature.
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wrote:

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They alternate with redcurrants and a neighbour has some BC bushes as well.

I live in suburbia and no-one keeps or overwinters bees in the area, unfortunately.

I have never pruned them.

They are planted next to the fence on the west side of the garden and the nearby south side is lined with spruce trees. I had thought at one time that perhaps they were too shaded.

Many thanks for your help. I never expected such a comprehensive reply and it has given me much food for thought. I have a neighbour who has a commercial beekeeping operation as a sideline (if you can call 300+ hives a sideline). I'll talk to him to see if he can overwinter a hive here next winter as an experiment. My ex used to overwinter bees in the back yard where we used to live and it really upset a lady down the street. The bees were drinking the seepage from her hot-tub and she was frightened of being stung - silly woman - they are quite safe unless you approach the hive. Our other neighbours liked the honey! We have such a late spring here and a short growing season. It is unsafe to plant outside until the 3rd w/e in May and I've had my runner beans killed by a snow storm in the middle of August. However, when Spring arrives, it does so with a bang. Again, many thanks. Graham
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