intransitive. To sprout or germinate, esp. abnormally or unseasonably; †to shoot up in growth.

To be or begin to be in boll. Cf. bolled, adj.2

intransitive. Of a seed or grain of a cereal crop: to germinate or begin to grow prematurely.

intransitive. Of a plant: to shoot up or grow quickly or excessively; to bolt. Cf. to run up 1a at phrasal verbs 1. Now rare.

intransitive. Of broccoli, cauliflower, etc.: to form a small, premature head.

To move or come as with a spring or sudden bound, to dart. Horticulture. To ‘run to seed’ prematurely.

Of a plant: to set to seed = seed, v. 3.