But most make up for the time taken to reach the flowering stage by producing some of the most colorful and spectacular displays to enhance any flower garden. They can cause the gardener a little more bother than annuals or perennials, as while they are growing in their first year it is necessary to fill in with annuals to keep their area in color.
Their great advantage is that their seeding stage produces new plants, which will bloom again two years later, making it unnecessary to plant additional seeds.
The alternative is to stagger planting after the first year so that there are always half the plants in bloom during the flowering season.
If the plants cannot be left outdoors all winter due to extreme cold then transplant them to a cold frame or even larger pots protected from the weather ready to be put back in their bed when spring arrives.
To provide a continuous growth of new biennials after planting, it is better to cut back on weeding and cultivation in the immediate area as the plants readily re-seed themselves so avoid disturbing the seedlings until they are identifiable and established.
If a really fastidious biennial patch is planted, it will be necessary to replace the plants with new ones each year otherwise just thin out the new plants to achieve your desired effect.
