Answer: This does sound like unusually large plants, possibly attributed to the variety you have grown, the amount of water they have received and the soil fertility levels or a combination of those. These plants do however tend to flop open when they bloom so many gardeners stake them or prop them up (usually when the plants are about half their final height) to prevent it from happening. As the blooms fade you should deadhead them (remove them) to encourage the plant to continue blooming rather than set seed, and once the flush is over you should trim the plant back hard. Then fertilize it and keep an eye on the watering. With luck you will have another good flush of bloom later this season.
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