I usually plant them in spring - as this year, and they have literally just shown their heads above ground, but a few years ago I planted the seed in Oct, and they grew really big - infact carried on growing slowly over winter, so that by early spring I had a green bushy hedge edging my veggie bed. They actually got a bit too over-enthusiastic and messy, so I tend to plump for more manageable spring sowings now

LCG