Short version:
Not for the faint hearted, this is a spicy rocket that really packs a punch. It’s perennial AND self-seeds readily. It grows in shadier conditions with poorer soil and lasts most of the year.
Arugula, rocket, rucola – whatever you want to call the regular, shop bought version is a complete wuss compared to the wild rocket, also called perennial wall rocket. Latin name Diplotaxis Tenuifolia.
Taste
Wild rocket is much punchier in taste, so be prepared. In the summer months it becomes so spicy that I can’t actually bear to eat it raw. If you’re at all unsure whether you like rocket you should probably avoid this. If you LOVE rocket, then this will definitely satisfy you. You may even find that you have to ‘dilute’ the spiciness with some more benign leaves, or some oil like cream or cheese. After gifting some to my neighbour, she sent it back over the fence in the form of an amazing pesto. That is literal by the way. We don’t often call each other or knock on the doors but conversations are held through the greenery and things are often passed in the gaps.
Growing
Growing in deep shade in clay and sand.
Seeds are easily sown straight into the ground a couple of weeks before the last frost. It germinates fairly quickly – around 2-3 weeks. It begins fairly spindly but by the second year if you cut it down to the ground it can become rather bushy. It does well in partial shade. In fact, some shade helps as hotter weather can cause the leaves to become very spicy. It does fine in poorer soils too.
This is a plant in its second year. This was February when it resurfaced. You can see it is fairly bushy at this stage.
Harvesting
Harvest the leaves as soon as you think the plant has enough to spare. You can also cut whole shoots for a more substantial harvest. This discourages flowering. This can be treated as a cut and come again plant for most of the year. Flowers can be eaten and smell rather sweet. Bees seem to be rather fond of them.
In June you can see the yellow buds on the end of the long spindly stalks. 
They can continue to flower until October. 
I didn’t have a sharp image of the flowers. They look much like the flowers of this Turkish rocket, except not as bushy. They still have the 4 petalled yellow flower but, as you can see from the other images, there a only 3-8 flowers on top of a longer thin stalk.
When the summer comes I stop trying to eat the spicy leaves. This means that flowers tend to grow. I like the smell of the flowers and my little one likes to pick them – though she won’t put them anywhere near her taste buds. This means that will an abundance of flowers the plant often goes to seed. I find the rocket springs up in the cracks of my flagstones. They become my much loved bonus plants. In the areas of the patio with low foot traffic I let them be. That way I don’t have to actually give up any garden space to the plant and still get to eat them.
Red veined sorrel and wild rocket populate my cracks. 
They don’t grow so well as they can get quite trampled. 
Under the paving stones is half a foot of sand so bless them for trying to grow.
The question now is why grow this over normal rocket? The perennial habit of wild rocket wins it for me. When the conditions are ideal this plant has continued to provide food well into winter and only had a little break for about 2 months before it was raring to go again. In my experience it can keep going till November and is back by February. It grows slowly at the beginning of the year, but it can be a useful green for the hungry gap. With absolutely no effort from me since planting 3 years ago it keeps coming back like a weed and just challenges me to eat it into submission. Just FYI, I lost and dug plants ups for other people’s gardens.
Not a Horticulturist 