Posted: 07/08/2017 at 20:11
I don't think I'd try and dig it now but Dave H is right about removing pernicious and persistent weeds so, if it hasn't rained, water as advised and then just fork out the main weeds and leave them in a pile to dry thoroughly before they go anywhere near a compost heap.
Rather than dig the whole bed, push a good strong garden fork in as deep as you can and wiggle it about to expand the holes. The holes will provide much needed air to the roots and also allow rain to penetrate deeper. Then mulch between roses and plants you want to keep with a couple of inches of well rotted manure or garden compost or bought compost mixed with some fine grit if you can get it.
Come autumn, mulch again when the perennials have died back and then leave it for the worms to work away. However, if you do decide to dig, autumn is the best time just to loosen the soil clods with a fork and then leave them to the frosts and mulch, as above, in early spring.
It may take a few years to get it looking and feeling like really good soil if the soil is really compacted but you should see an improvement in plant growth and health by next spring and every passing year.