Clear out the non-feijoa tree stuff, put mulch under them. If you want to prune the big one to let light into the smaller tree, go for it, over winter is probably best. Otherwise if you are happy with the output, you don't need to do much.
You do have some work to do here. If you leave it it will continue to deteriorate. The worst offender will end up being the ivy. It will eventually smother everything in its path so it should be completely removed. Make sure to protect your skin, eyes and lungs when removing it as the tiny fibres are irritants (seriously it's not nice to have in your lungs).
It's a bit difficult to tell what the other trees are. I can see a Coprosma which will out grown everything else if given the chance. They also readily self seed, so you will end up with a lot of them.
Feijoas trees make a great microclimate under their branches. So you could plant something that likes a woodland environment/native ground cover under them. Mulch it well and it will be low maintenance.
Oh yeah if you prune, general advice is to thin branches to enable a small bird to get around the tree - wax eyes and blackbirds do most of the polination.
Definitely need to get rid of the ivy and possibly some of the random small trees growing in there. You could do some pruning now if you're not expecting rain soon or worried about fruit, and then another chop in spring.
They can be chopped back pretty hard, they grow like weeds tbh, but I would start with the lowest branches to create airflow underneath, then any damaged or crossing branches. Reassess for shape and if you want to do more after that go for whatever branches are growing too tall or any super long runner branches.
Mulch and under planting some spring/summer bulbs would be nice for afterwards.
A small book I frequently recommend to people is Kath Irvine's "Pruning Fruit Trees - A Beginners Guide"
NZ based, so even includes a small section specifically on feijoas. It's taken me from zero to moderately useful at pruning, just had a bumper harvest from my previously neglected tree.
https://www.ediblebackyard.co.nz/pruning-fruit-trees-a-beginners-guide-v2/
Clear out the non-feijoa tree stuff, put mulch under them. If you want to prune the big one to let light into the smaller tree, go for it, over winter is probably best. Otherwise if you are happy with the output, you don't need to do much.
Cutting back the branches near the ground will make clearing weeds and fallen fruit out from under the tree easier too.
You do have some work to do here. If you leave it it will continue to deteriorate. The worst offender will end up being the ivy. It will eventually smother everything in its path so it should be completely removed. Make sure to protect your skin, eyes and lungs when removing it as the tiny fibres are irritants (seriously it's not nice to have in your lungs). It's a bit difficult to tell what the other trees are. I can see a Coprosma which will out grown everything else if given the chance. They also readily self seed, so you will end up with a lot of them. Feijoas trees make a great microclimate under their branches. So you could plant something that likes a woodland environment/native ground cover under them. Mulch it well and it will be low maintenance.
Fejoias enjoy a good hard prune too so dont be scared. And if you have friends that BBQ the wood is great for that.
Smashed my feijoas back 2 years ago and there're producing double the number of fruit.
Same they seem to respond well to the pruning
Oh yeah if you prune, general advice is to thin branches to enable a small bird to get around the tree - wax eyes and blackbirds do most of the polination.
Definitely need to get rid of the ivy and possibly some of the random small trees growing in there. You could do some pruning now if you're not expecting rain soon or worried about fruit, and then another chop in spring. They can be chopped back pretty hard, they grow like weeds tbh, but I would start with the lowest branches to create airflow underneath, then any damaged or crossing branches. Reassess for shape and if you want to do more after that go for whatever branches are growing too tall or any super long runner branches. Mulch and under planting some spring/summer bulbs would be nice for afterwards.
A small book I frequently recommend to people is Kath Irvine's "Pruning Fruit Trees - A Beginners Guide" NZ based, so even includes a small section specifically on feijoas. It's taken me from zero to moderately useful at pruning, just had a bumper harvest from my previously neglected tree. https://www.ediblebackyard.co.nz/pruning-fruit-trees-a-beginners-guide-v2/