A promise came in the mail today, a package of Verbena bonariensis seeds. Tall verbena. I love it, so long as I can get it to germinate and be mature enough to plant out early enough.

This annual needs a stratification period for really successful germination. Stratification is the process of tricking the seeds into their normal growth cycle of spending several cool months in the ground before spring. To do this, the seeds are sown on the surface of damp potting soil, covered in plastic or a glass cover, allowing air circulation and popped in the fridge for a few weeks. When removed they still may take two – three weeks to germinate and then growth is slow. However the wait is worth it.

 This process of stratification triggers the seed to break dormancy when it comes into the warmth. The cool period in the damp also helps the seed coat break down enabling the seedling to break free from its capsule and begin to grow. It is important to keep the soil damp and to have air circulation because both oxygen and water are required for this process.

This tall verbena is an attention getter and mass planted makes a dynamic statement. I don’t grow it often because truthfully I don’t have an ideal spot to plant it. I tried for several years before I got the timing and stratification right but then when I did, it was thrilling to watch the butterflies flock to it. It also makes a lovely cut flower.

For several years after I had it in planters on my patio,I would have volunteers come up through the bricks but they never had time to mature so although the seeds will tolerate cold temperatures, it requires a longer growing season than we can give it under natural conditions.

The most impressive planting I have seen of verbena bonariensis was in front of Chateau Laurier in Quebec City. It was mid-October and a biting wind was blowing off the St. Lawrence but there it stood sturdy and purple.

I will plant these seeds now and leave them in the fridge (a cold garage would do) for a month. They will come out in February and sit in a warm sunny spot inside until they germinate. When large enough and the greenhouse temperatures are above freezing, I will transition them there until time to plant them out.

My Queen Anne’s Lace or Ammi majus will require the same treatment but not quite for so long.

Make sure you check the germination instructions on seed packages because often this process is all a tricky seed requires to jolt it into action.

Verbena bonariensis in my garden and mass planted in front of Chateau Laurier, Quebec City