By Scott Canning, Director of Horticulture and Special Projects
Welcome to the joys and the challenges of April in Santa Fe! April is not winter, but in Northern New Mexico, it isn’t quite spring, either. This is a truly schizophrenic weather month, with balmy days forcing fruit trees into bloom, followed by hard, sharp freezes that blacken tender new growth and break our hearts. To paraphrase Bette Davis, when it comes to gardening, Santa Fe “ain’t no place for sissies.”
Spring bulbs and most perennials can tolerate these freezes, so try not to worry about them too much. With fruit trees, if they aren’t small enough to cover on cold nights, there’s not much to be done. We learn the hard fact that some years will leave us with the fruit crop severely depleted. If choosing fruit trees for the home orchard, find the latest-blooming varieties to try to escape late frosts. The fruit trees planted at the Botanical Garden at Museum Hill were chosen by Tracy Neal with bloom-time a strong determining factor. In fact, our ‘Signature Plant Guide’ is now available, and it is a great guide to recommended plants, including our fruit trees, for gardeners in Santa Fe. Find it in our Gift Shop on your next visit.
For gardeners almost everywhere, April is a challenging month. The to-do list is the longest in April and May, and a gardener can be overwhelmed and wonder, “Where do I start??” A guiding principle can be to remember which garden chores are most time-sensitive. If you intend to transplant any perennials, the sooner they are moved, the better. It is “furniture moving” season in the landscape. And pruning should be hurried to completion. Remember that your spring-blooming trees and shrubs should be pruned only AFTER they bloom; otherwise you will be removing this year’s buds and blooms. That group includes forsythia, lilacs, mockorange, currants and viburnum; basically anything that blooms before mid-June.
The forsythia is blooming, and that is an old-time sign that it is time to prune your roses. The observation of seasonal change as a clue to inform the timing of farming and gardening chores is a time-honored technique. It informed the Old Farmer’s Almanac. It continues today as “phenology,” the study of the timing of the biological events in plants and animals such as flowering and migration, and it overlaps with the study of climate change. I encourage you, as a curious gardener, to learn more at the USA National Phenology Network, and the ongoing project initiated by the Chicago Botanic Garden, Project Bud Burst. The blooming of forsythia was also used as a sign that it was time to apply pre-emergent herbicides to lawns to inhibit the germination of lawn weeds. Today, corn gluten-based products are a safer alternative, but the timing remains the same. And of course there are alternatives to lawns, too! A subject for another day…
Cold-hardy perennials can be set out in the garden now. This includes snapdragons, hollyhocks, Dianthus, statice and stocks. Help them adjust to their life in the great outdoors; they may have been coddled by the plant nursery under cover to speed their growth and be less cold-hardy than usual. Set them out on mild days and bring them in on nights that drop below about 28 degrees for a week or ten days to “harden” them before planting out. They can be left out on slightly frosty nights above 28 degrees without harm. Pansies are treated like cool-season annuals and should also be “hardened” before planting out. They can cheer a gardener’s heart in April. I love the little Johnny-jump-ups that are smaller, closer to the species form of Viola, and even tougher than hybrid pansies. Orange pansies have the strongest fragrance, and I have a weakness for them, too. Try all types in bowls or pots near an entrance-way or in a well-traveled garden area.
Continue cleanup of flower beds and adding compost and organic fertilizer to the landscape. The soil should be dry enough now to work them in without harming soil structure.
In the vegetable garden continue sowing cold-hardy crops like radishes, carrots, beets, turnips, kohlrabi, parsnips, spinach, Swiss chard and peas. It is safe now to plant out transplants from the cabbage (mustard) family like kale, Brussels sprouts and cauliflower. Don’t forget herbs that are cold hardy like parsley, culinary sage, thyme and oregano. If the plants are tiny, harden them off, too. Late in April is usually safe to plant potatoes since they won’t emerge above ground until after the last frost.
I am seeing vegetable plants like tomatoes, peppers and eggplants offered for sale at supermarkets and big-box stores, but unless you have a protected growing space to hold them until we have truly warm and settled days, don’t succumb to the temptation: Our last frost date is close to mid-May. If they are planted out in April they will be killed by frost, or, at best, languish in the chill. A strong transplant set out the third week of May will do much better than trying to jump-start the season with these nightshade plants. The same holds for okra.
Set a date in late April or early May for your irrigation turn-on, and keep an eye on the weather to guide you on the amount of hand-watering your garden requires until then.
And lastly, and firstly, and in-between, keep after the weeds! Annual weeds love spring, and some complete their life-cycle in a stunningly short period of time, producing seeds. And so I repeat the mantra on weeds: “One year to seed, five years to weed”. Need I say more?