Heart shaped and star shaped cucumbers are grown in much the same fashion Square Watermelons are, with a special mold placed over the fruit while they are growing.
They are common everyday garden varieties of cucumbers grown in a different way.They are a great novelty and are excellent for catering and attractive salads. My kids love them.
A cucumber while growing on the vine, will adapt to the shape of the container it is placed in. It must remain in the shaped container while developing on the vine, otherwise it will flow back into its natural rounded state. Any type of cucumber will suffice.
Grow your cucumbers as you normally would.
Once the vines start producing small cucumbers place the tubular molds over them and that's about it - watch them grow into big designer cucumbers.