My final touch is going to use these artificial berries (also found in the dollar store) to give some texture and visual contrast.
In this case, less is more. I'm just going to put a couple of stems into this arrangement. I really like the effect that a little white in the berries manage to pop out and give contrast to the deep colors.
Tuck the second stem under the pumpkin lid, burying it a little deeper than the flower heads.
The overall design is very pleasing. Rotate it around, seeing if you need to add anything else. Fall arrangements always seem more clustered, allowing the rich autumn colors to blend rather than letting too much green from the foliage show.
Finished! This fall centerpiece would be beautiful as wedding or shower arrangements for your tables. Keep in mind, however, that fresh pumpkins will not last as long as the flowers - you may have to transfer into another container after the pumpkin begins to get soft.
I like to guard against possible table stains by placing a clear or colorful plate under the pumpkin.
Check your pumpkin daily for spoilage and add water to the flower foam to replace what is drawn up by the flowers.
I always spray my finished flower designs with a flower sealant such as Finishing Touch. It seals in the moisture. This is especially important around fall time, since furnaces suck moisture out of the air (and out of your flower petals!)