The hot season is approaching here in Salt Lake City, and it’s time to start thinking about a watering schedule for your outdoor plants. How much is enough? How much is too much? The experts at Millcreek Gardens, everyone’s favorite garden center in Salt Lake City, can clue you in. During a summer afternoon, up to half of the water can be lost to evaporation. The best times to water your outdoor plants are in the morning or evening, so the roots have a chance to absorb most of the water. Applying mulch around your plants can also help conserve a lot of water and reduce watering needs.
Trees and shrubs have deep and extensive root systems so they should be watered less frequently and for longer periods of time. The optimum time to water is just before water stress occurs. To determine sub-surface soil moisture, use a soil moisture probe, a screwdriver or long metal rod. The probe will easily penetrate moist soil but stops when it hits dry soil. The soil should be moist to a depth of 18-20 inches for trees and shrubs. If you encounter resistance, your plants may need a deeper drink.
Allowing water to penetrate deeper into the soil profile encourages deeper rooting and a more drought tolerant plant. Frequent, light irrigation will lead to plants with a shallow root system that are more prone to water stress. When using sprinkler systems, about one-half to 1 inch of water may be required weekly for shrubs and smaller trees of up to a 4-inch trunk diameter. Large trees with a trunk greater than 4 inches in diameter may require hundreds of gallons of water per week. For newly planted trees and shrubs, water frequently until the root system is established. If we get more dry winters here in Utah,don’t be afraid to water your trees once or twice in the winter when soil temperature is above 40 degrees Fahrenheit. Your trees and shrubs will thank you when it’s time to wake up from dormancy in the spring. When it does snow, it’s also a good idea to shovel some extra snow around the base of trees and shrubs, giving them more water to drink as it melts.
Cacti & Succulents:Of course, these native plants love sun 24/7, and they don’t need much water either. Many varieties only need watering once a month. Succulents store water to survive drought conditions. During times of drought, the water held in the leaves, stems and roots is slowly used to keep the plant alive. A succulent in a pot does not have the deep, expansive root system it would have in the wild. Potted succulents should be thoroughly watered from top to bottom, then allowed to dry. Check the soil for moisture using a soil probe or the tip of a wooden pencil. If the soil is dry, halfway down the pot, it is time to water again. Don't ever let any type of succulent stand in water. After watering, drip trays or saucers should be emptied of any excess water. Come visit Millcreek Gardens to see our many indoor and outdoor varieties that have pretty flowers on top and cute foliage.
Geraniums: Geraniums prefer moist but well-draining soil. Check soil moisture with a moisture meter, or by sticking your finger about an inch into the soil. Water when soil is on the dry side.Geraniums used to come in red, pink or white, but today, you can get geraniums in purple, orange and many different shades of pink. You also can often get your choice of variegated geraniums. At Millcreek Gardens, we love geraniums so much we have an annual 99 cent geranium sale every May, just in time for Mother’s Day and spring planting. We still have some left, come by today to grab a few geraniums for yourself and to share with neighbors!
Black-Eyed Susans:Black-eyed Susans do not need much extra water once they're comfy and established in the garden. You do need to water them when you first plant them, though, to help the plants grow new roots and settle in. Water well whenever the top inch of soil around the plants is dry.These perennial darlings grow in clumps up to 3 feet tall, filling their space with cheerful beauty. There are dozens of kinds of black-eyed Susans, but the best-known are yellow with a cone-shaped brown center.
Sunflowers: Kin to the black-eyed Susan, giant sunflowers can grow more than 10 feet tall, spawning scores of seeds for next year — if the squirrels and deer don’t get them first. Although sunflowers require a lot of water to germinate, they only require an inch of water per week during the growing season. Use a watering nozzle to easily water once a week until the top 6 inches of soil is moist.
You should water these sun-loving outdoor plants from time to time when soil is dry, but if you forget, they’ll probably be just fine. Water more freely during the hot and toasty summer months of July and August in Utah.
Hostas: Hostas are hardy plants that grow quickly, allowing you to divide them to spread around or share with neighbors. Their delicate flowers on long stalks last throughout the summer, bringing color to areas where plants are hard to grow. In an ideal hosta garden, the plants would receive generous watering all season long. A slow, deep soaking of around an inch of water per week through the growing season is perfect. A single deep soak every week is always better than multiple, light waterings. Deep watering encourages the roots to grow deeper into the ground where they can still find moisture during short periods of dryness. Frequent, light watering encourages the hosta roots to grow near the surface of the soil where they can quickly dry out even in short dry spells.
Hostas can tolerate periods of dryness, if they are otherwise healthy. However, hostas that are never stressed from lack of water will grow bigger, faster and will hold up and look nice longer into the season. Usually, they can fend for themselves, but watering during periods of dryness will certainly help your hostas look and grow their best.
Lily of the Valley: Hiding inside deep green pointed leaves are stalks that hold a dozen or more tiny, delightful white flowers dangling upside down, seemingly on a thread. For all their dainty appearance, these flowers can be trod upon, accidentally mowed, dug up by your pooch and more, and still proliferate. If the soil is relatively dry at planting time, you can soak the plants in cool water for several hours before planting. As with all transplants, lily of the valley should be watered weekly for the first 4-6 weeks after planting. Lily of the valley is an extremely tough plant, and it will grow in almost any type of soil or climate. Though the roots love moisture, once the plants are established, they are quite drought tolerant. Ideally, Lily of the Valley prefers consistently moist but not soggy soil. Water whenever the soil begins to dry out due to a lack of rainfall and/or hot weather. Soil that is too dry will impede the plant’s growth and flowering.
Impatiens: Impatiens bring an instant burst of color wherever you put them — in boxes or pots out front, along a walkway or even in the house by a window. While impatiens will quickly wither and die if left in the Salt Lake City sun, they do like a little bit of sun, and plenty of light. Be sure to water them frequently. You’ll remember when you notice them drooping sadly. Watering Impatiens should be consistent but doesn’t need to be daily during comfortable temperatures in late spring and early summer. When temperatures are in the high 80’s or 90s, it is more likely these flowers require watering every day. Mulch helps retain moisture so you may not have to water as often. Quickly soak the area where impatiens plants grow but don’t water them excessively.
We hope this short guide on how much to water a few of your outdoor plants in the Salt Lake Valley will help you decide what to grow this year and where in your yard to place it. For an amazing selection of outdoor plants and the best advice in Utah on caring for them, stop by Millcreek Gardens today.