Let the planting begin!
May is the perfect time for planting perennials in Colorado. This is the time of year that you can plant very small stock, and provided that you care for them well, they will generally be robust and mature by the end of their first summer. Be sure that the new plants are watered daily for the first month, and when we get into the hot days of summer, don’t let the new plants get too dry this first year.
This is also an excellent time to divide perennials that are getting a bit crowded, or if you are just looking to propagate some new plants. Daylilies are very easy to divide, and now is an excellent time to do so – the earlier in May the better. Dig the clump that you want to divide, and set the clump in a pail of water for a few minutes. The reach down into the pail, and carefully tease the plants apart from each other. Get these plants into the ground and watered ASAP, and be sure to keep them from drying out for the first couple of weeks. The same method can be used to tease apart clumps of many grasses, but do this only in the evening or on cool days, as those first few hours and days after dividing are critical for the survival of many grasses.
There are many perennials that will benefit from occasional division of clumps, and May is an excellent time for most of them. However, there are exceptions. Don’t divide Iris yet – let them bloom first and then divide them in June when they are done. Same with Peonies – they should be divided either after they bloom, or at the end of summer when they are going dormant – I seem to have the best luck dividing after they bloom and giving them lots of TLC that first summer.
May is a good time to prune many shrubs as well. Once the Forsythia are done blooming, prune them right away. They can be pruned as hard as you want to if you do so right away when they are done blooming, and you will get flowers again next year, as the flowers come on the previous year’s growth. Lilac should also be pruned as soon as they are done blooming, though in most areas around here that isn’t until June.
As soon as the trees start to put their green on the branches, it is good to start pruning for shape. Spring is when the root spends most of it’s energy for new growth, so it makes sense to get that pruning done before the energy is wasted on growth that you don’t really want anyway.
If you have a pond and fish, May is a critical time to make sure that the water is in good shape, and that you get the pH and algae under control right away. Barley is a good but slow assistance to the high pH problem that we will generally see, but there are other good products available that work much faster. There are also good products to chemically control algae, though once your pH is healthy, the algae will become much less of a problem.
Happy planting and dividing!
