Gardening tips for April
By Linda Langelo
Colorado State University Extension
Now that COVID-19 has most all of us working remotely from our homes, here are a list of tips to help you get outside and enjoy the garden. Most of your perennials are putting on new growth. The first ones putting on new growth are the spring flowering shrubs, late spring and early May perennials.
When should you remove the dead stalks/stems?
If you see new growth starting either on the stem or at the base of the plant, then prune out the dead. If the growth is coming from the base, prune the stem to the ground without injuring the new growth.
If the new growth is showing on the stem, cut above that new growth.
It is best to divide most perennials in the spring, once they just start showing some new growth. Don’t move iris, that will stress the iris plants. Wait until summer to do that.
However, I am listing a few of the most common perennials you can divide in spring, including: beebalm, bachelor button, black-eyed Susan, blanket flower, bleeding heart, bugleweed, butterfly weed, catmint, coneflower, coral bells, coreopsis, dianthus, daylilies, hellebore, hardy geraniums, hosta, lambs ears, mums, phlox, salvia, shasta daisy, sedum and speedwell.
What perennials, besides iris, should you wait to divide in the summer? Columbine, peony and Oriental poppies.
For perennials such as Russian sage that have taproots, dig up the new seedlings coming up in early spring while they are small. Otherwise, do not divide them. It is best to start with a new plant.
For roses, wait until after Mother’s Day in May before attempting to prune. Remember pruning encourages growth. If you prune too early before the last frost, then you will damage the most vulnerable new growth. Your rose has used up energy to do this and can set the rose back. You can check the last frost date in your area at https://cmg.extension.colostate.edu/Gardennotes/748.pdf.
Be sure to rototill the garden, when the soil is not wet. You can start some greens in container plants now. Otherwise, there are a lot of other crops that can be planted in your garden now. When planting seed, the lighter and smaller the seed can be placed directly on the soil and just lightly tamped down to make good contact. Plant seed that is larger such as peas or corn deeper. Plant peas an inch deep and plant corn two inches deep. You can view the CSU Plant Talk on gardening for cool season crops at https://planttalk.colostate.edu/topics/vegetables/1806-growing-cool-season-vegetables.
And a vegetable guide for every detail you need to know for growing both cool and warm season crops is available at https://cmg.extension.colostate.edu/Gardennotes/720.pdf.