I was in a nursery a few days ago. It was celebrating a great spring and early summer by passing on some tremendous values in close-out plants for annual color. So I thought to myself, “Why not? A fellow can always stand a little more color.”
If you’ve read this column very long, you’re going to see me write the words “Plan before you plant.” It’s a way of making sure that each and every plant you bring home from the nursery really will have a spot available for it.
In this case, however, I went against my own rules. I simply picked out the plants that I liked — those that were at the best prices. I figured I’d find a way to work them in once I got home.
I do a lot of my gardening in containers. It has been a way of providing my annuals the very best potting soil and to elevate them to a position of prominence in my garden without building berms and retaining walls. It has been a way of keeping my plants out of the way of dogs, cats and rabbits.
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So for those reasons and more, I have probably 50 large pots that find their way into our landscape every year. This year, I knew I hadn’t come close to using them all, so I chose these new plants with happy abandon.
Choosing potting soil
You’ll find a lot of premixed potting soils in garden centers, hardware stores and even in groceries. However, most of those potting soils are very heavy, meaning the soil particles are small, allowing the soil to absorb and hold way too much water. For that reason, and because of sheer volume, I mix my own.
I’m frequently asked what the components of the perfect potting soil might be, and I’m not sure my answers are ever the same. However, in most cases I use 50 percent sphagnum peat moss (sold in bales), 20 percent finely ground pine bark mulch, 10 percent well-rotted compost, 10 percent horticultural perlite and 10 percent expanded shale (for ballast).
That makes a really good, well-draining potting soil, and it can easily be modified to accommodate everything from ferns to cacti and succulents. I use sandblasting gravel (smaller than BB-sized) mixed in, in place of the compost, for my cacti and succulents.
A soil mix like that is very porous, and that means you’ll have to water it frequently. My plants are watered three or four times per week, daily in extreme heat. With all that watering, and because the soil mix is so loose, nutrients are leached away very quickly. I apply a diluted solution of a high-nitrogen, water-soluble fertilizer every other time I water.
Sun, part-sun or shade?
Plants grown in containers are a little more vulnerable to summertime leaf scorch. However, flowering plants and those with colorful foliage almost always do better if they’re given at least half a day’s sunlight. Whenever I can, I put container color where it will receive sun in the morning, and shade or diffused shadows in the hottest part of the day.
When I have a spot with afternoon sun that’s calling for color, I choose my plants much more carefully, and I watch them closely for the first couple of weeks. If they start to bleach or burn, I move them into more shade. Sometimes it happens very rapidly, so be prepared to rescue your plants if they begin to struggle.
Best for summer color
The great news is that breeders have been developing scores of new plants for hot-weather parts of the world (Texas certainly included!). Here are some of the best choices for potting (or planting directly into beds) right now for color until frost. I know I’ll miss a few, but this will provide a good start.
Taller vertical plants for the centers of your pots: purple fountain grass and other ornamental grasses, firebush, Gold Star esperanza, tropical hibiscus, pentas, copper plants, sun-tolerant coleus, SunPatiens (sun-tolerant hybrid impatiens), crotons, purple alternanthera, cleome, celosias, lemon lollipop and taller types of basil or rosemary.
Rounded plants for the mass of the container: shorter varieties of pentas, bush forms of lantana, caladiums, Cora periwinkles (most disease-resistant strain), angelonias, Diamond Frost euphorbia, globe amaranth, globe basil, rosemary, wax begonias, bloodleaf, Dahlberg daisies, ornamental peppers, perilla and Mexican heather.
Trailing plants to tumble over edges of the pots: fanflower, purpleheart, moss rose, trailing purslane, trailing lantanas, Blue Daze (Evolvulus), Joseph’s coat and trailing rosemary.