About French beans

• French beans are the unripe fruit of any kind of bean, including the yardlong bean, the hyacinth bean, the winged bean, and especially the common bean (Phaseolus vulgaris), whose pods are also usually called string beans in the north-eastern United States, but can also be called snap beans. 
• Runner beans are the only exception and are treated as a different type of bean.
• French beans are self-pollinating and do not have the setting problems that can occur with runner beans.
• They come in 3 types and 3 different colours: 

• Pencil pods, which are round in cross-section and usually stringless - these are divided into yellow 'waxpods', purple pods (which turn green when you cook them) and green podded varieties
• Flat podded types
• Filet or needle beans - these are the exceptionally thin Kenyan type.
• The filet, waxpod and purple varieties are considered best for flavour.
•  The last two have another advantage, in that they are easy to spot when picking time comes around. 
• There are also varieties grown mainly for drying (e.g. haricots), as well as varieties that are usually shelled like peas (flageolets), very popular in France. 
• Climbing types should be grown the same way as runner beans.