This is a sign of ripeness but there will be varying degrees of colour depending upon the species. Luckily most species flower and set seed over a long period so there is time to witness the various the various stages of ripeness. If in doubt place a small paper bag over the developing seed head. This will ensure that the seeds are captured. Germination of Geranium seeds can be quite erratic, so do not be too quick to assume the seeds are not viable if it takes a long time for seedlings to appear.
Some species require the seed to be stratified to initiate germination.
This is a small species with grey-green foliage. Ballerina ' has greyer leaves and purple flowers with red veins and dark eyes, while ' Lawrence Flatman ' has darker eyes still and usually darker petals. Both are good plants for a rock garden or well-draining soil of a bed or border. G. grandiflorum, G. himlayaense var. It is ideal for the informal bed or border or even growing cascading over the sides of a raised bed.