[caoimhin]

I think the swede I have planted have bolted. The plants each have a flowery shoot about two foot high. Never planted swede before so I'm not sure. Any ideas.

[Belfast]

yes they can bolt.

"Category:Turnips

Turnips, swedes, and Rutabaga,
These names are used somewhat interchangeably,
The vegetable known as rutabega in the U.S. is known as a swede or turnip here. This is Brassica napa, (as is oil seed rape amd some kales). It has blueish green grey leaves which are not hairy. They have yellow flesh.

The other vegetable known as turnip is Brassica rapa and has green hairy leaves. This is also know as 'white turnip, and is related to Chinese cabbages. They generally have white flesh. Both have a mild sweet taste, which is at its best when the vegetables are young.

Turnips are quick to grow and undemanding, providing vegetables at times of year when other things are scarce.
'White turnips' such as Milan Purple Top are one of the first vegetables ready to eat in summer and 'swedes' such as Tipperary Turnip are good to eat out of the garden from September until the end of March, when they start to bolt."

http://www.brownenvelopeseeds.com/index.php/wiki/grow_veg/Category:Turnips/

Tips for Growing Turnips and Rutabagas
"Both turnips and rutabagas are cool-weather vegetables and are commonly grown as fall crops. Turnips can also be planted in early spring, but they tend to "bolt," or produce seeds, and turn woody during hot weather."
http://homeideas.howstuffworks.com/vegetable-gardening/tips-for-growing-turnips-and-rutabagas.htm

"KOHL RABI

The origins of this root vegetable's name - the German for 'cabbage turnip' - describes its taste, which is a rooty, delicate, cabbagy flavour. It is highly nutritious and much more drought resistant - and therefore slow to bolt - than either swede or turnip. It grows fast as long as its water supply is steady and prefers a light soil. Firm the ground well, as for cabbages, and sow in drills at monthly intervals with latest sowings in September and October for a winter supply. Thin to 10-12in apart or sow in plugs, two or three seeds to a plug and plant out when growing strongly. Harvest 8-12 weeks from sowing. "
http://www.dailymail.co.uk/home/gardening/article-1168563/Monty-Don-grow-3.html

[Liparis]

Usually, but not always, Swede are grown to be used at a small size, normally a little over the size of a tennis ball, turnips are grown as a larger root. If you have grown swede a few things may have contributed to them bolting. Hot, dry weather and allowing them to get too large, possibly a combination. You refer to having planted your swedes; did you plant them or sow them? By that I mean did you sow the seed straight into the ground where they are to grow or did you sow them then transplant them?
Planting would work with other factors to encourage bolting of the crop. Normally they shouldn't produce flowers the first year but several factors would incourage that.
Bill.