Can I replace old blackcurrant bushes with new ones in the same earth, or should I grow something new/wait a year or so first?

all you need to do is mix/dig in new compost horse manure and a feed off blood fish and bone over the whole are as it bound to be depleted of nutrients

Jensen, it's best not to plant fruit bushes as with many shrubs in the same place as old ones. With the pruning you have done, you could continue by cutting all of your bushes to ground level, water on a fungicide around the stumps, top dress with some well rotted manure and wait for new growth to show. Should there be enough growth to form a good shape in June dress around each one with 2 ounces of blood, fish and bone or John Innes base fertiliser. Should this fail you can dig the whole roots out in the autumn.

Thanks for your replies. Sorry I edited the question, just to express it better, before I noticed them.

For future reference a tip about pruning. What you do with blackcurrants is to remove about one third of the old wood down to the base after fruiting is finished, and take out any weak or spindly shoots. Fruit appears mainly on the wood that grew the previous season (the opposite of red currants) so you need to take care you don't cut it all off! They need a tremendous amount of feeding and it looks as though yours haven't had as much as they would like, which is why the more recent growth looks spindly. Before you replace them I would try feeding them with a rich mulch of good compost or well rotted manure, and a dose of potassium sulphate to encourage flowers and fruit. If you can't get the mulch then a dose of Growmore is better than nothing. It won't help too much with fruit this season but your new wood should grow more robust and do better the year after. If you are iffy about doing this just try it with one of them and compare it with a new one - but they can live a very long time with good feeding. Nettles make good feed if you can get them. I read about somebody who abandoned some old bushes to the weeds. They got overgrown with nettles and after a few years began fruiting well again with no further treatment!

If you simply replace the plants and treat them the same as these ones you will get the same results.

As Stera says, blackcurrants are greedy plants. I feed mine in early spring and after harvesting the fruit in July, I prune them and give them another feed. After thirty years, they are still growing and cropping well.

You are right Steragram, they have not been fed atall. I have some really good compost which has been ready for about two years, so I will probably use that.
Do you think the plants will be alright, in spite of how the base of them looks? I do not know much about it, but I wondered if a professional would say they do not look healthy.
I wish I had not pulled out the nettles in our garden last year. I will certainly use them as feed when they grow back.

I see what you mean and honestly I don't know the answer. Did the bush look healthy when it was in leaf? It looks almost as though there might be some rot or canker or something - don't know if they are susceptible to that. You should follow Dr Bobs advice because he knows what he's talking about, especially for the affected one on the left but I would leave the other one and feed it up as it doesn't seem to be affected, but don't hold your breath for much fruit on it this year.

If you were going to replant you'd need to find a fresh site anyway so why not buy one new one and put it somewhere else as insurance?

Re the nettles, don't ever throw them away, they make excellent compost or you can soak them in a bucket of water for a few weeks and use the (very smelly) liquid diluted as plant feed.

If you do ever want to get rid wait until they have died down. The roots are very easy to see as they are bright yellow and come out easily and don't sting!.

Thanks again Steragram.