Question: Is it too late to prune my roses?
Pat J., Artesia
Answer: No, it’s not too late. There’s more harm in pruning roses too early than too late. That’s because pruning stimulates a flush of new growth, which is wonderful—as long as you’re past the risk of more hard freezes in your area. That new green growth is especially prone to frost damage, and damaged branches would then need to be pruned back again. The optimal window for most rose pruning is 2–4 weeks before your expected last frost. Even when pruned at this time, an abnormal late freeze can do considerable damage to your rose plants, but it is much less likely.
According to https://www.plantmaps.com/, the average last frost in Las Cruces is early April, in Artesia and Roswell it’s mid-April, Los Lunas and Albuquerque early May, and Taos early June. Many successful gardeners do holiday pruning, meaning in Las Cruces they might prune their roses around Valentine’s Day, St. Patrick’s Day in Albuquerque, and Tax Day in Taos.
I see two drawbacks to waiting until your area’s expected last frost date to prune your roses: 1) You’ll likely have to prune off some new growth, which will include some new buds. You’ll still get flowers, but it’ll take more time for new buds and flowers to develop. 2) You might wait so long that new flowers are already opening, and then you put off pruning until next year, like I do.
Many roses are impressively drought- and heat-tolerant. There are also flowering shrubs in the Rosaceae family that are native to New Mexico and are great options for low-water landscaping. Native or not, now is a great time to add a mulch (like woodchips, leaf litter, pine needles, etc.) under your bushes and around trees, and as a moisture-holding layer on the tops of your veggie beds.
I subscribe to a new newsletter from Divine Earth, a commercial pruning and landscape company in Albuquerque (https://divineearthnm.com/), and I was delighted to get their quick and clever tips on rose pruning: 1) ditch the fabric and rock, 2) add some compost and mulch, 3) water, and 4) prune most roses back hard. I love that three out of their four “rose pruning tips” are about growing roses more sustainably. Any time is a great time to remove artificial weed barriers in ornamental landscapes. The trouble with them is that they’re either too flimsy to keep weeds from popping through, or they do a great job keeping weeds under control, but at the expense of keeping water and air from moving down into the soil. That means the soil and ornamental plant roots in those areas are sure to suffer. And, after time, soil that blows in on top of that barrier can harbor weed seeds that grow just fine on top of the fabric or plastic. Landscape designers and installers across the region are officially giving up on weed barriers in urban landscapes.
It’s also always a great time to pull back landscape rock from around the base of roses and other ornamental plants and replace it with a nice, thick top layer of woody, fibrous mulch. If you compost your kitchen and garden scraps, you can sprinkle a layer of that on top with your mulch. Check out NMSU Extension Guides H-110, “Backyard Composting” (https://aces.nmsu.edu/pubs/_h/H110/welcome.html), and H-164, “Vermicomposting” (https://aces.nmsu.edu/pubs/_h/H164/welcome.html), for helpful info for beginner composters.
Water your established roses to a depth of 18–24 inches about once every 2–4 weeks in spring, depending on your soil type and environmental conditions like wind and temperature. When temperatures get higher, it’s recommended that we water our roses and other shrubs every 1–3 weeks from May through October. For newly planted roses, water will be needed more frequently and always to the same depth.
Special pruning note for climbing roses: wait until after bloom to prune. That’s because climbing roses bloom on 1- and 2-year-old wood, so if you prune before bloom you’ll be cutting away the current season’s flowers. Other roses bloom on new branches that develop in spring.
Roses can be pruned back harder than most people think, so don’t be shy. If you’re worried, try your own mini trial at home by pruning some branches lightly, pruning some branches back severely, and leaving some alone. Take photos before pruning, after pruning, and throughout the season and share them with me on social media: @NMDesertBlooms. NMSU Extension Guide H-165, “Growing Roses” (https://aces.nmsu.edu/pubs/_h/H165/welcome.html), has lots more information about rose types and their care.
The Albuquerque Rose Society offers free pruning demos each year, and several are still coming up this season: March 14, 15, 21, and 22 from 10 am–3 pm (http://www.albuquerquerose.com/). I’ll attend one of these sessions and post video to the blog version of this column next week (https://nmsudesertblooms.blogspot.com/).
For more gardening information, including decades of archived Southwest Yard & Garden columns, visit the NMSU Extension Horticulture page (http://desertblooms.nmsu.edu/), follow us on social media (@NMDesertBlooms), or contact your County Extension office (https://aces.nmsu.edu/county).
Marisa Thompson, PhD, is the Extension Horticulture Specialist for New Mexico State University and is based at the Agricultural Science Center at Los Lunas.