Month: July 2024

Smart Watering Helps Plants Beat the Heat

Maryland Grows4 Comments

Cole Porter was right. It’s too darn hot. 

As we watch the high temps stubbornly refuse to budge, it’s tempting to hunker down indoors and let our gardens go. Don’t. Those plants really need us now.

The best thing you can do to help is to water well. That means watering deeply less often.  

a show of water from a hose - watering a garde plant
Water at the base of plants to soak the roots.
Photo: Miri Talabac, UME

Daily sprinkles do more harm than good, stimulating shallow roots, which have a harder time drawing up the water plants need.  

Light watering also encourages tomatoes and peppers to develop black, leathery blossom end rot. 

So water vegetable plants deeply twice a week. Dial it back to once a week when things cool down.   

Watering in the morning is best as is directing water to the base of plants.  

If you planted new trees or shrubs this year, water them slowly and deeply at least once a week to soak the root ball. Use a soaker hose, a 5-gallon bucket with a few nail holes, or a hose on a slow trickle. 

a green tree bag placed around the trunk of a tree
Tree bags help to keep trees and shrubs well watered. 
Photo:  Joe Murray, Bugwood.org

And no, rain is not enough. Here are a few more tips on watering trees and shrubs.

If you’re growing anything in containers, check those pots daily. Most need to be watered every day.  And do some supplemental watering in your perennial beds. Everything is dry, dry, dry.

Smart tools make watering easier and use less water.

Soaker hoses – made from recycled tires – water plants slowly at the base of plants so you don’t lose water to evaporation.  

Drip irrigation does the same and lets you customize water zones. I can’t say enough good things about the drip irrigation system on a timer in my vegetable beds.  

a drip irrigation system set up in a raised bed garden
Drip irrigation saves time and money.
Photo:  Robert Cook

Rain barrels are a godsend. An eighth of an inch of rain on the average roof fills a 50-gallon barrel.  That’s free water, folks. I have four rain barrels and plan to add two more.  

a rain barrel next to a garden
Rain barrels capture rain from roofs to reduce water bills. 
Photo:  Rutgers University

Avoid watering with sprinklers. Overhead watering can promote disease and cause the loss of up to 80 percent of water to evaporation. 

Here are some more tips on conserving water and using smart tools. 

In addition to boosting plants’ water needs, heat zaps plants in other ways. 

Have you noticed flowers falling off your tomato plants? Sustained high temps prevent pollination, causing plants to jettison their blooms. Don’t worry. Flowering and fruiting will restart when it cools.

Trees react to high heat, too. Many are raining down leaves. This is a natural stress reaction. In fact, trees don’t need all their leaves. They’re just shedding some to cut down on maintenance. 

Unless the leaf loss is dramatic, those trees will be just fine.  

Lawns are feeling the heat as well, browning here, there, and everywhere. They are not – I repeat not – dead. Lawns naturally go dormant in high heat and will spring back with rains. Only new lawns need to be watered.

If you’d like to boost your landscape’s resistance to heat and drought – and the need for supplemental watering – add some water-wise plants.  

Deep-rooted, well-adapted native plants are a great choice. So are plants with fleshy leaves or roots, blue leaves, skinny or fuzzy leaves – all natural adaptations that mean these plants need less water. Think sedum, iris, lavender, threadleaf coreopsis, and lamb’s ear. 

Here are some tips for creating a more climate-resilient landscape.

Watering wisely and picking the right plants will help you build a more heat-resilient landscape that can not only beat the heat but look good doing it.     

By Annette Cormany, Principal Agent Associate and Master Gardener Coordinator, Washington County, University of Maryland Extension.

This article was previously published by Herald-Mail Media. Read more by Annette.

Q&A: Reduce the Height of an Arborvitae?

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Arborvitae (Thuja sp.). Photo: Jason Sharman, Vitalitree, Bugwood.org

Q: I need to reduce the height of an arborvitae…. I might take around 5 feet off the top because it’s too big. When should I prune?

A:  While late winter or early spring is generally a good time to prune conifers (needled evergreens), in this case timing won’t matter much, because the amount you want to remove is more than the plant can handle. Instead, it may be better to replace the plant with a smaller-growing option.

Most conifers, including arborvitae, do not regrow foliage when it’s lost due to heavy pruning, deer browsing, or crowding from being planted too close together or too close to a wall or fence. Unlike broadleaf evergreens (boxwood, holly, euonymus, etc.), they don’t have dormant buds along the older stems, lying in wait to grow if the branch or foliage beyond them is removed.

Once the foliage is gone and bare wood is visible, it’s not coming back on that part of the plant. This is the reason why deer-browsed arborvitae are easy to spot, developing a shape sort of like a stemmed flute glass, because the parts the deer can reach become stripped of foliage and never fill back in again, even as the out-of-reach tops get wider.

As conifers age, it’s perfectly normal for the innermost branches to become quite bare, as those older leaves shed over time. They are deliberately jettisoned by the plant because they are being progressively shaded by the outer shell of live growth, so they cost the plant more to keep alive than the meager photosynthesis energy they get back. This will be exacerbated if the plant is sheared, where the foliage tips are lightly trimmed to give the plant a more manicured look, because that makes the layer of foliage casting shade on the plant’s interior even denser.

Pruning cuts that take off that outer layer or shell of younger growth on the branch tips will result in permanent bare areas. Once the foliage is gone from that inner wood, it will not regrow, even if sunlight now reaches the interior due to pruning cuts. This also applies to the main leaders. Reducing the height of a tall arborvitae will stunt the top growth and give it a permanent gap or flat-looking top. If this isn’t really visible from where you typically view the plant, then it’s not necessarily a problem (assuming the pruning cuts seal-over well and don’t develop wood decay). Otherwise, nothing will give the plant its former shape back.

Fortunately, there are lots of compact and dwarf conifer varieties on the market these days. A couple conifer types, like yews, will be able to rejuvenate after heavy pruning. Even so, it’s still best practice to select a plant that should fit in a given space in the yard without relying on pruning to make it fit.

I acknowledge that there are many gardeners that inherit poorly-chosen plants in their new yards, but if or when it comes time to replace them, research your options to make sure you won’t run into the same problem down the road. Plants never really stop growing, though older specimens can slow down. Due to a reduced growth rate, dwarf and miniature cultivars will stay much smaller over the same amount of time as their full-size counterparts, even though some dwarf cultivars can also get larger than you’d expect a few decades after planting.

By Miri Talabac, Horticulturist, University of Maryland Extension Home & Garden Information Center. Miri writes the Garden Q&A for The Baltimore Sun and Washington Gardener Magazine. Read more by Miri.

Have a plant or insect question? The University of Maryland Extension has answers! Send your questions and photos to Ask Extension. Our horticulturists are available to answer your questions online, year-round.

Tiny tomatoes perfect for patios (and canine companions)

Maryland Grows2 Comments

Just a quick post this month to shout out the virtues of the first tomato plant to produce ripe fruit for me this year: ‘Veranda Red’ patio tomato.

This little cutie is only 18 inches high, and in fact would be shorter if it was growing in full sun instead of the partial sun on my deck. I have other plants with green fruit ready to turn red that are less than a foot high, and the container team at the Derwood Demo Garden has a plant only about six inches high that has ripe fruit.

Patio tomatoes as a group mature at less than two feet, and grow well in smaller containers like window boxes or gallon pots. The larger the pot, the larger and more productive the plant will be, but they will be loaded with flowers and fruit even in a small container. Most varieties are cherries, though a few make larger salad tomatoes.

‘Veranda Red’ is a relatively recent hybrid, but some patio tomatoes have been around for years. A few varieties I found in a quick search include ‘Tiny Tim,’ ‘Micro Tom,’ ‘Tumbling Tom’ (and the rest of the Tumbling series), ‘Orange Hat,’ the ‘Patio Choice’ series, ‘Red Robin,’ and there are many others. Try doing a search on ‘patio tomato’ or ‘micro dwarf tomato,’ or check your favorite seed catalog. You may also find plants at a garden center (I know Bonnie Plants has their own variety and others are likely available – just read the tags carefully to make sure you’re getting a dwarf plant).

These tomatoes are a great option for folks who don’t have much growing space, maybe a balcony or window box or a postage-stamp sunny patio or yard. They don’t produce as much as a full-size plant, but more than you would think!

Now, I have a bunch of full-size tomato plants already growing in my community garden plot, none of which have ripe fruit yet, but they’re getting there. Why bother with patio tomatoes? Well, sometimes a plant, like a person or a pet, just fills a particular spot in your life. Fifteen months ago I inherited a cocker spaniel named Freckles who used to belong to my mom and stepfather. She’s made a new home with us and definitely found a home in our hearts. Freckles loves many fruits and vegetables and is especially fond of tomatoes – she can sniff out the plants well before they have any fruit and will drag us to them. Last year she hunted for fallen cherry tomatoes around our neighbor’s big potted plants and alerted me to some volunteers that sprouted in unexpected spots in my landscape. So I thought it would be nice if she had her own tomato plants closer to home. We make a stop on the deck after a walk to see if any new ‘Veranda Red’ cherries have appeared. She approves!

By the way, I did get to eat one of the tomatoes myself, and can report that it was very tasty. Recommended, even if you don’t have a tomato-eating dog.

By Erica Smith, Montgomery County Master Gardener. Read more posts by Erica.