Very hardy plant asparagus. There are various hybrids available now so I can suggest you go on-line & have a browse through the specialist growers. Do not buy plants in bags from garden centres. Buy fresh 'crowns' direct from the growers, they despatch at the correct time of planting.
I bought 30 crowns x 3 varieties three years ago so this Spring will be our first harvest. It has been well worth the wait. There is a bit of a photo of our asparagus bed in my GoY album.
I put a ton of well rotted compost & stable manure into the trench's before planting the crowns as they will provide spear's for at least 20 years.

If you don't mind waiting one year longer for your first spears, I'd recommend some of the F1 hybrid seed now available. Usually only £2 or £3. You may only get 30 seed or so in a packet, but usually you get 100% germination if you sow them carefully in pots or modules.
Grow them on in pots or in a carefully prepared seed bed the first summer, and then you can carefully unearth them in the second spring and plant them as one year old crowns.
This costs a fraction of buying in crowns, and in my experience when you order a dozen crowns, at least two of them are often very poor quality plants.

I was prepared for one or two weaklings included in 30 crowns Bertie but all arrived 100% perfect & healthy, subsequently 3 years on they are all in great shape. It's the garden centre crowns in plastic bags that I would avoid, you cant see if they have the essential 'bud' or not.