Expert: Mike Mascio - 5/3/2007

Question
QUESTION: I live in Whitecourt, Alberta, Canada and I love petunia's.
My question is how can I get the to reseed them selves in my flower bed to come up next spring.  I was told that they will reseed and all I did last year was let them die in my flower bed and this spring when the snow melted, I pulled out the dead roots and tops but didn't disturb the top soil very much. I hope that they will reseed like i've heard.
thanks for your help. Erica

ANSWER: Erica, you did exactly what you needed to do. Once the plant matures, it will form a seed pod if the flowers are not deadheaded. The pods eventually fall to the soil, hybernate over the winter, and germinate in early spring. The only variable is whether or not the seed is viable. Some hybrids will reseed, but the new seedling is a mutant rather than an exact replicate of the parent plant. But the pod literally holds hundreds of tiny seeds. There is a strong probability that an acceptable percentage will germinate.

Good luck, and have a good week.

Regards,

Mike

---------- FOLLOW-UP ----------

QUESTION: Mike, thank-you for responding to my question so fast. My next question is when will I see them growing,if at all and how do I look after them when and if they start? Can I water my flower bed before I start to see any green? The soil that I have put in my flower bed was maniure so the clover can take over at any time.  Any suggestions to prevent that from happening except for picking them out by their roots.  Thanks Erica.

Answer
Erica, you will need to water the soil and keep it moist until you see the seeds germinate. Growth should begin in mid-May. If you do not see anything by May 25th, the seeds most likely will not germinate.

Once they do sprout, you will need to thin them to one seedling per square foot. Petunias need at least 12" between them. Given their growth habit to spread, they will fill in within 4-6 weeks.

Once they reach 6" tall, mulch the soil around them with shredded leaves or bark to keep the soil moist. This will also prevent weed seeds from germinating. Once they begin flowering, fertilize them every 10 days with a fertilizer high in phosphorus to promote blooming.

I hope this helps. Please write again if I can ever be of assistance.

Regards,

Mike