Maureen - so easy - you can use different coloured icing on the cup cakes - and I figure 3 and 4yo do better with cupcakes than a piece of cake.
Then everyone gets the same amount iyswim.
I cheated and used ready made icing.
The stalks are made of fondant icing with green food colouring kneaded in.
I also put a ribbon to tie the bunch together.
I also managed to get some butterflies to decorate the stalk part of the bunch.