Leaf beet, aka perpetual spinach, is a type of chard with green leaves and slim stalks that can be harvested for a much longer period than annual spinach. With successional sowing leaf beet, like chard, can be harvested all year round. It is very winter hardy and doesn't bolt in the summer (until its second year in which case you can grow on for seed).
'Erbette' is a popular variety with market gardeners as it is acceptable to most customers in lieu of annual spinach which is much more fiddley to grow.
