Pruning and training During the first year, do not harvest
asparagus spears. Allow all the shoots to grow to fern for the
summer. This will build up carbohydrates in the roots and
support new spear growth the following spring. After the frost
turns the ferns brown or during January if ferns are still
green, prune them down to the ground and rake them out. Dispose
of the ferns rather than leaving them in the field to avoid
overwintering pests. Repeat the process each year thereafter.
However, before allowing the plants to fern, you can harvest for
a period of time. To conserve garden space, the tall asparagus
ferns can be supported on a trellis made of wire.