DENVER - Spring is in full swing. Tulips and daffodils are at their peaks. The strange and exotic crown imperial (Fritillaria imperialis) is also blooming rather majestically.
This bulb, native to mountainous regions of the Middle east, blooms with a "crown" of orange or yellow flowers atop its three-foot stems. The plant carries an odd "foxy" scent. Like tulips and daffodils, the bulbs of crown imperials should be planted in fall, so mark your calendar.
If you love asparagus, plant it now. An asparagus patch takes several years to get up to speed. Once established, however, it will produce a bounty of asparagus for several months in spring. When harvesting, cut the new stalks all the way to the ground when they're six to eight inches tall. If you let them get any taller they will be tough and woody.
The stalks are the future flowering stems of the plant. Keep picking them until mid May or so, depending on the weather. Allow about ten stalks to grow and mature to replenish the plant. The plants grow about four feet tall and have pretty, feathery foliage and tiny yellow flowers. Asparagus plants require little care and your patch will thrive and multiply for decades.
Plants that do require attention now include roses, shrubs and some small shrubby herbs.
Trim roses as needed--mainly to remove dead canes. Shrub roses shouldn't be pruned radically. Just trim them for shape. Hybrid tea roses require a harder pruning--down to about a foot or so--to force them to branch.
Small shrubs such as 'Goldmound' spirea should just get a light trim for shape. Its bright golden-green leaves are an asset all season and is topped in summer with clusters of small pink flowers.
Lavender, rosemary and santolina are also shrubs even though we call them herbs. Their woody stems can be trimmed now to promote bushiness. Take out dead branches and prune for shape.
Some shrubs die back all the way to the ground in winter and regenerate from the base. These "die-back" shrubs include butterfly bush and blue mist spirea. In a mild winter they won't die back all the way but they benefit each spring from a hard pruning.
Start your fertilization program on your patio plants. Pansies, dianthus, snapdragons, sweet alyssum and cineraria should be fed every ten days to two weeks. At this time, we're doing a half-and-half mixture of a "grow" formula (with higher nitrogen) and a "bloom" formula (with higher phosphorous). Deadheading is also important to keep these cool season flowers blooming vigorously.
© 2017 KUSA-TV