Tag Archives: heat

Help Plants Beat the Summer Heat

It’s hot here. I thought I would never say that. And sure, it’s not as hot as Phoenix, but even mountain communities in the Southwest can warm up in summer months. When the temperatures hit the 90s, the humidity stays below 25 percent, and the winds never subside, vegetables and ornamental plants get stressed.

columbine northeastern exposure

In May, this columbine was blooming and healthy! It’s a little stressed now. Columbines grow naturally under the shade of trees, and they need deep water as temperatures rise into the 70s and higher. We mulched around the plant and put it in a northeast-facing location to help it survive summer.

Often, our first reaction is to throw more water on a plant. Sometimes, that’s what they need. Wind, sun and heat dry plants more quickly. Native xeric plants are adapted to take some of the parching sun and wind, and sometimes a gardener can overwater a plant. Here are a few tips to keep xeric plants cool, healthy and happy during the heat of summer:

  • Start with the right plant for the right spot. That means not only a native selection, but choosing sun vs. shade or the right drainage. Most xeric plants can take plenty of sun, but some need partial shade. And most don’t take kindly to wet feet, or roots that fail to dry between watering. Wet feet can happen with overwatering or if you place lavender in poorly draining soil at the bottom of a hill, or hide it under a bush that grows quickly and shades it within a year. You also can plan ahead to take advantage of shade. It’s getting too hot for my lettuce, but we’ll plant some more north of the fence holding the pole beans as soon as they get a little taller.
garden plan for shade

The sun is so bright, it’s reflecting off the spot where we hope to get some shade for lettuce and spinach. You can see the bean seedlings on the other side of the foreground fence shadow.

  • Follow the sun. When you plant in spring, the sun and shade patterns are different than they will be in mid-July and August. So keep in mind the sun’s direction and any plants or structures that might help shade a plant late in the day, when the sun’s rays are their hottest. Remember that deciduous trees might be nearly bare when you plant, but loaded by mid-June.
  • When helping a new plant get established, the typical care instructions might not apply. The plant goes into a sort of shock, much like when you recover from illness or injury. All plants need a little more water, as well as extra sun and wind protection until established. We’ve often used portable lawn chairs to provide filtered shade over new plantings in the afternoon. Old sheets or landscape fabric also work.
  • Use containers. If you have a plant that’s more susceptible to heat stress, place it in a container. You can move it around throughout the summer based on the sun’s path. Of course, if you really love the plant and have lots of time on your hands (and wheels under a larger container), you can move it around during the day, giving it morning sun and afternoon shade.

    tomato in container

    The tomato seedlings I planted in containers are doing better than many in the ground. The patio and house warmed them up during cool nights, but provide shade now on hot afternoons.

  • Water in the morning. It’s tough to find time before work, but watering early in the day loads your plant up, preparing it for the heat. And try to keep soil evenly moist. If you have a slow drip system, the irrigation can run while you get ready for work. Cover the drip hose with a nice, thick layer of mulch and the mulch will slow the water’s evaporation and help keep the ground cool. And as I’ve said before, it’s good to keep an eye on tomatoes and other vegetables and to have someone care for them if you leave town. Once the fruit sets, you can’t drown the tomato to make up for a few days of heat and underwatering. They’ll punish you.

Finally, drink some iced tea, flavored with a small bit of fresh mint. Oh, wait, that’s for me…

Harden Off Houseplants for Their Summer Vacation

When warm days—and especially warmer evenings—finally arrive, our houseplants are more than ready to move outside. It’s easy to tell. They look a little leggy and droopy. And although I said they are ready for a summer vacation, in reality, they’re taking an eight or nine month winter vacation inside. Because plants grow naturally outdoors, of course!

Geranium hardening off outside.

Geraniums are annuals in our climate, but I love how they bloom indoors in sunny windows all winter.

I really only have geraniums (Pelargonium spp.) right now, along with one canna that I keep in a huge container. It’s my ode to the tropics, and although it hasn’t bloomed again, I love it purely for the leaves. This year, I plan to cut it back and divide it, giving a few bulbs to family members who live in a warmer climate. Maybe dividing and cutting it back will force energy into blooming. We’ll see!

tropicanna canna

This Tropicanna canna is from Tessalaar Plants, and would have trouble making it here, plus uses too much water. But I have kept it alive in a container purely for the leaves. The flower is bright orange and gorgeous!

One reason I have few house plants is time, another is water savings, and most of all, it is lack of space and containers. My succulent-collecting husband has taken up most of the sunny space with propagation, and used lots of the containers. But I enjoy his cactus habit!

The main point to remember when bringing all of your houseplants out for the first time after their “winter vacation” is to introduce them slowly to the outdoor climate again. For most houseplants, that means bringing them into a shady, protected area first or leaving them out on a relatively calm but cloudy day. And bring them back in the first few nights if there is any chance that temperatures will approach frost.

aloe vera plants

Aloe vera plants harden off on a partly sunny day in preparation for the summer outside.

The cacti may be able to sit in full sun from the start; in fact, they probably need it. But if it gets blazing hot, bring them in before day’s end, and don’t subject them to cool desert evenings until they’ve at least been outside through dinner hour. If you don’t want to make the indoor/outdoor trek every night, you can cover your most sensitive plants with landscape fabric until they harden off and the nights warm up. The fabric also can help shade them during the hottest part of the day if temperatures shift while your plants are acclimating.

Make sure your plants are healthy and ready for the move outdoors. I cut my geraniums back quite a bit and usually add a little bit of soil or compost to the pot. If they’re in really bad shape, I will repot them. But they tend to bloom better if slightly root bound. Then I give them a good drink and put them in dappled or partial shade the first few days, gradually giving them a little more sun.

geraniums cut back for hardening off

I cut these geraniums back severely and added some compost, because they did not fare as well as my others. They need repotting next year. Note the requisite gardening gloves and phone…

Use Mulch To Conserve Water In Your Garden

When you put away a gallon of paint or the leftovers from dinner, you always cover the container. By sealing the paint can or plastic storage container, you lock in moisture. It keeps your paint from drying out. Same goes for your spaghetti with pesto (not to mention sealing in the “aroma”…).

Your plant roots can benefit from their own covers, and that’s where mulch enters the picture. Much like the top layer of paint in a can, air dries out the soil at ground level. Add wind and heat, and water can evaporate quickly from desert gardens in particular. Mulch helps insulate the soil to keep it cool and minimize evaporation. The layer of mulch also protects the area around the plant’s roots from the forces of nature. In other words, when the rain comes, it won’t pound the ground, eroding dirt away. Instead, it hits the layer of mulch, then trickles down to the ground. Use an organic mulch and each time it rains or you irrigate, the water carries some nutrients for the roots to take into the plant as well. Need more reasons? Mulching cuts down on weeds, and weeds compete with your plants for water. Plus, they are such a pain.

shredded bark mulch

Mulch cools and moistens barberry, photinia and ice plants in Albuquerque, N.M., bed.

To truly insulate and cool plants takes about three to four inches of mulch material. It depends on the type of material you want to use. If the mulch is fine, such as bark cut to smaller than an inch in size, go only about an inch or two deep. The same goes for grass clippings. Your roots also need some air to thrive! So be sure to avoid use of landscape plastic under your mulch in any areas where you will plant. The plastic is great in walkways, but not in your beds or under trees.

When piling mulch around plant or tree roots, cover the entire area to which the roots extend. For trees, you need to go out about as far as the tree’s canopy. And don’t place the mulch all the way up against the trunk of the tree or stem of the plant. Leave a small opening close to the plant.

mulch around tree

Water is less of a concern in this Northeastern garden/iris farm. But I would worry about how closely the mulch comes to this tree trunk.

Mulches also can look attractive and add to landscape design. Be careful about mulches you choose and social media posts with ideas for repurposing materials as mulches. Some are harmful if applied directly to vegetables and other plants or introduce weeds to your garden. And if your helpful neighbor offers fresh chicken or horse manure, remember that you shouldn’t apply it hot. Add it to your compost, and eventually to the vegetable garden.

gravel around yucca

In the desert of Tucson, the rock around this xeric yucca is probably more for looks, erosion control and night-time heat retention.

We’ll break down some types of mulch in a future post, but if in doubt, check with your local extension office or master gardeners.

No Moisture and High Temps

It looks like New Mexico is facing its worst drought since the 1880s. It’s possible that in those days, legends like Pat Garrett and Billy the Kid rode near here, headed to the Rio Ruidoso in hope of watering their horses. I’m certain that at some point, our few acres served as a farm, judging by the rolling terrace and the mystery shed. At some point, there was an orchard by the river, evidenced by a dozen or so old stumps.

apple tree in small orchard

Small orchard in late fall. Notice an old stump off to the right, behind the fence stake. Tim is building up the wells around the trees and we’re reinforcing the fences to keep munching deer out.

The younger fruit trees in our current orchard didn’t produce fruit last year because of a late freeze and I foresee the same problem this year. It’s so warm right now, and will be for close to 2 weeks, that the trees think it’s time to bud out. Since our last freeze date is around Mother’s Day, it’s likely that freeze will again destroy any hope for fruit and my canning jars will sit empty on the shelf.

This all amounts to a bummer for us; we don’t face anything near the hardship of the people who endured drought during the 1880s. We can buy fruit and all the jelly we need at grocery stores in town. It would cost much less to make our own, but at least we do not depend on the land.

spanish-broom-in-rock-garden

The ornamentals also are confused. See the dry, nearly dead grass in the background? But the warm temps against the rocks fooled this Spanish broom into blooming in February!

spanish-broom-flowers

It’s nice to see these pretty yellow flowers from my office window.

The real problem with the record high temps and low humidity is the fire danger. In April 2011, the White Fire swept through Ruidoso Downs and within a few hundred yards of our home. We still see the damage from our front yard and it humbles us. The wildlife population still is lower than normal, though we have had steady visits from a herd of about 15 deer and the occasional elk.

white-fire-damage-deer_web

The mountains on the left show remaining damage from the 2011 White Fire in Ruidoso Downs, N.M., as deer graze on grass. On the right is a red-twig dogwood, a favorite plant for winter color.

My hope is for rain or snow, but continued warm temperatures. That would ensure that the fruit survives the season (and gets some natural watering) and that the fire danger remains low. It also means delicious apricot jelly for a year?

Maximize Xeric Plant Choices with Microclimates

There already are plenty of fabulous choices for drought-tolerant plants, but we found that our choices narrowed a little when we moved into a slightly colder zone. We’re quickly discovering that our new location has a shorter growing season, but that it can get warm here, so unpredictability makes it a little risky but a lot fun.

With microclimates, I figure we can push the envelope on a few of our favorite xeric plants. First, let’s talk about microclimates. In essence, a microclimate is a pocket of an area that can vary in temperature and exposure to the elements. A microclimate can be large or tiny. An example of a large microclimate might be the area that runs along the river. The grass there is still green and the leaves remain on some of the trees. A combination of shelter, shade, lower elevation, and moisture contribute to the cooler temperatures you feel when you walk through there on a sunny day.

river with grass

Microclimates occur along rivers because of dappled shade, lower elevation, and extra groundwater.

Microclimates can be as small as the few feet you have to plant in front of your south-facing wall or the inside of the plastic bottle you place over a seedling to absorb sunshine and maintain humidity for a mini-greenhouse effect.

bottles_micro_web

Tim covered these transplants with cut-off plastic bottles and set them in a window for a mini-greenhouse effect.

We brought a pad from our spineless prickly pear along and to be sure it made it here, we planted it against the rock wall on the northeast side of our garden (facing southwest) to maximize sun and minimize wind exposure. You also can use microclimates to make plants more drought tolerant. For example, put a plant that needs a little more water than nature usually provides in summer where your terrain naturally comes to a slope and slight pool, creating a natural well. And avoid placing a plant that can’t handle drought on a high southwest-facing spot with no protection. In my area, at least, you might as well be putting the plant up on a clothesline to dry before nightfall.

Micro_prickly_web

This transplanted spineless prickly pear is happy in its southwest-facing wall location.

Here are a few more tips for making microclimates work for you and your plants:

  • Try even large trees and shrubs on south-facing walls to add a half-zone of heat. You’ll likely have more success if you buy a plant that’s slightly established (not a bare root, for example). An unusually cold winter might kill the plant or prevent fruiting or blooming, but it’s worth a try.
  • Take advantage of the shade from the heat-loving tree and fill in around the bottom with perennial or annual bedding flowers that need a little bit of cool shade in summer. They might even provide some natural mulch or protection for your tree on cold nights. Columbine is a great example; it’s a gorgeous flower that grows naturally in higher elevation forests, but might thrive under the dappled shade of a landscape tree.
  • Use raised beds and containers to create microclimates. Raised beds that run east to west warm up faster in the spring, and any new vegetables planted on the south side of the beds should beat others to the punch. You can move containers around to create microclimates for plants indoors and out, wintering over cacti and other heat-loving plants in south-facing windows, but setting them out on the patio in spring. Just remember that pots, especially clay ones, dry out more quickly. That’s fine for succulents, but can become a problem for thirsty annuals in the heat of the summer.
  • Use mulch or landscape fabrics and plastic to cover ground or  seedlings, adding some warmth and protection.

Mostly, what works for a friend or neighbor might not work for you and vice versa. Slight variations in elevation and exposure can make big differences to a plant’s health and happiness. But if you’re willing to take a few risks, you might be able to enjoy your favorite plant right outside, or inside, your window.

geranium_web

I’m wintering over a few geraniums. This one loves its location on a south-facing wall right by the window. Notice another transplant behind it with a plastic bag and my dog enjoying a sunny microclimate on the floor to the left…