Question
My mother planted Marigold's (in NJ)on the side of the house 20 years ago. She planted them once and they come back every year. The patch also gets bigger every year. I pinched some tops this spring and they grew at my house (in CT). My Mom has passed and yesterday I had to sell the house but I did pinch a bunch of tops for the seeds and will be trying to grow them at home.

Is this something that happens regularly? An annual that acts like a periennal.

Answer
John, a perennial is a plant that comes back every year from the base of the plant's root system. They often multiply either from bulbs or replication. That is why they need divided every three years.

Annuals, on the other hand, only propagate from cuttings or seeds. In the case you have described, the plants are just going through the normal life cycle that all annuals do. They are self-seeding. For a seed to germinate, it needs three conditions; dormancy, protection, and moisture. Most annuals that self-seed, including marigolds, drop their seeds throughout the growing season. Most of those require a minimum of six months for their dormant period. To stay viable without germinating, the seed requires cool temperatures and darkness. Winter, a blanket of snow, and fertile soil provide both of these needs.

In summary, the marigolds are not acting like a perennial in the true sense because they are not sprouting from the roots or bulbs. Instead, they are letting mother nature take care of the seeding process, and rewarding you every spring with new plants.

I hope this answered your question. Please write again if you ever need assistance.

Regards,

Mike