Lori Pelkowski, the Midnight Gardener, gardens and writes in historic Bucks County, Pennsylvania.

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Help Your Container Plants Beat the Heat
by Lori Pelkowski       #Advice   #Summer

The Profusion series gives the vigorous habit and unabashed blooming we expect from zinnias in a tight, compact, dainty-looking plant. This tough guy will bloom continuously until frost.

Do your container plantings need a facelift during the dog days of summer? When summer temperatures reach into the 90s for days on end, plants in containers wilt in the heat just like we do. Sprucing up overworked container plants and worn-out soil can help keep them colorful and cheerful even the hottest summer.

Try these pot and basket rejuvenating tips, along with heat and drought tolerant plants, to freshen up your containers during the long hot season.

When your container annuals pass their prime, water them thoroughly and wait a few hours. Then remove them from the container and trim the roots by one third. Cut back straggly plants by one third as well, and don't worry if this includes cutting off flower buds. Cut off all the dead and fully bloomed flowers. This will invigorate the plant.

The dirt in your garden beds may be great for growing plants in the ground, but plants in pots are a different story. When used in a container, even the best garden soil tends to harden to the point of being deadly to plants. Garden soil can also contain insect larvae, weed seeds and harmful spores. Purchase soil that is specially formulated for potted plants to provide the correct levels of aeration, water retention and trace nutrients.

So re-pot your newly trimmed plants with fresh soil mix. Bagged potting soil may be enhanced with plant food and a moisture retainer. These mixes are perfect for outdoor containers. If you can't find them, use regular potting soil and add a time-released plant food like Osmocote and a moisture retainer such as Soil Moist. Follow the package directions for using the correct amounts for the size of your container.

Fill the bottom of extra large containers with gravel or small stones before adding the potting soil to prevent them from toppling. Also do this for any containers that do not have drainage holes. Fill two thirds of the container with potting soil, then water it. Add more soil until the container is three-quarters full. Arrange the plants in the container, making holes to accommodate their roots if necessary. Fill in soil around each plant, and be sure to plant it at the same level it was previously. Water the pot well and add more soil as it settles if needed.

A layer of mulch on top of the potting soil helps protect the planting from losing moisture through evaporation. Shredded hardwood mulch works well, and can be purchased by the bag at a local garden center. Or try decorative mulches such as pebbles or packaged moss. Be creative!

Put newly trimmed and repotted plants in a shady area to prevent them from going into shock. They should look radiant and ready for their permanent spot in a few days.

Water potted plants when the soil just below the surface feels dry. Commit to watering your containers once a day, maybe even twice during the heat of the summer. Plants in a sunny location may need water several times a day. Watering in the morning and early evening will prevent sunscald and water spots on the leaves. When the soil surface is dry but before the plants begin to wilt, water slowly and thoroughly, until water runs out of the bottom of the pot. Shallow window boxes and hanging baskets dry out faster than deep containers. Try not to let any containers dry out completely.

Don’t despair over summer-weary containers. Try these easy tricks to revive them. Or, if your local garden center still has healthy-looking plants, try these pretty annuals that laugh at the heat.

Osteospermumis a tongue twister that means South African daisy. These beautiful plants are smothered with pretty flowers with unique purple eyes, and they love the sun. This is a great choice for the middle of a large container, between the tall focal point and the low trailers. The South African daisy comes in pink, purple, cream, white, yellow and orange, and smiles right through the hot, dry summer.

The South African daisy is stunning on its own, or paired with trailing plants like petunias. Try it with white for a calm effect, or deep purple for some extra punch.

Verbena is a lovely hanging plant whose purple, hot pink, red or white flowers beautify baskets, window boxes, and container edges. They barely notice heat and drought, and revive quickly if they wilt. The purple is almost blue; a large bowl of red, white, and purple verbena makes a patriotic addition to a patio table. Try them in boxes along the railings of a sun-soaked deck, or in simple baskets hung in the perennial border for added height.

Feathery gaura flowers look like butterflies floating over the container. It is shown here with pink verbena and white lobularia. Verbena and lobularia are similar in habit and flower type and can be interchanged to customize the color scheme of the pot.

Everyone is familiar with the marigold, lovingly grown by children in paper cups. The common marigold comes in some very uncommon color combinations, and sizes from mini to pompom. The small and medium flowered marigolds are best in containers. Like the South African daisy and the verbena, marigolds love being deadheaded and will respond well to being cut back if they start getting tired.

Portulaca is a low-growing plant with pointy, succulent leaves and small flowers in colors from magenta to cream. Portulacas are true sun worshippers that love hot, dry conditions. They look lovely hanging over the edges of containers, baskets and window boxes that have the sun beating on them all day. Shear them back to about 3 inches if they get straggly.

Gazania, also known as the treasure flower, has bright daisy-like flowers. They are easy to find in garden centers, and they transplant well. Plant gazania in the hottest, windiest, most exposed site -- they'll love it. The flowers are marvelous, and come in yellows, oranges, pinks, bronzes and reds, with black markings at the base and stripes of contrasting color down each petal.

The Zinnia Profusion series rewards gardeners with hundreds of single, star shaped flowers. Unlike the larger zinnias, Zinnia elegans is a medium-sized plant with tiny leaves. It grows in an elegant globe shape with cream, yellow, orange or red flowers. The orange looks great with purple mealycup sage (Salvia farinacea 'Victoria Blue'). Both will bloom freely even through summer drought, and the color and texture combination can't be beat.

Nasturtium boasts loads of cream, yellow, orange, pink, red or mahogany flowers that are often splotched with contrasting colors. All parts are edible, and add a peppery flavor to otherwise bland green salads. A low growing, trailing plant, the nasturtium has intriguing, heart-shaped leaves. It is a fast-growing annual that seems to thrive on neglect. Nasturtiums are a cheerful presence in containers or hanging basket.

Nasturtiums love to hang, trail and ramble. Use the heart-shaped leaves and pretty flowers to garnish outdoor meals. The entire plant is edible with a subtle peppery nip.

Photos courtesy of Proven Winners.


Posted: 08/07/14   RSS | Print


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