Customize Your Own Cocoa Liners

It’s time to start work on this year’s container plantings. Many years ago, I received a triple-tier garden planter as a gift. It was six feet tall with wire mesh bottom and decorative sides, and was meant for use with cocoa liners. Of course, cocoa liners break down by the end of a single season, so they became an annual cost. The size of the largest two levels meant this was a hefty expense. Because I am thrifty (read: cheap), I decided to experiment with a different method. I am sharing my success with you in this blog.

The condensed version: Make your own liners. Sew them into place. Line the liners with landscape fabric. Fill with soil and plant.

Now for the non-condensed version: Instead of continuing to purchase pre-cut liners, I bought an entire roll of cocoa mat. These are available in different sizes; I purchased the largest one I could find. It was a substatial initial cost, but the length of the roll meant I would have material for many years into the future. I used a scrap piece of material (old tablecloth) to cut a pattern for each of the three tiers. I thought I could use landscape scissors or pruners to cut the liner material, but it was tougher than I thought possible. I dulled several pairs of scissors and a pair of metal-cutting shears before I thought to wet the material. I used a large galvanized tub intended for farming use. Bingo! Soaking the roll in water for about 30 minutes made the trimming process easy, if somewhat messy. Warm water made it ever easier.

If you don’t want to purchase an entire roll of cocoa liner, check out better nurseries or farm supply stores. Many will sell this material by the foot during the spring gardening rush. This photo was taken years ago, so the price shown is not accurate in today’s market.

This was one of my first cut-to-size attempts. The jagged edges show where I tried to use scissors. The smooth edges were where the liner was cut after soaking.

Once the cutting process was complete, I placed those pieces into the appropriate level of the container and secured it into place using clear fishing monofilament and an upholsterer’s needle (looks like a regular sewing needle but 6 inches long and sturdy). It was simple to push the needle through the cocoa mat and wrap it around the metal frame. The clear monofilament was invisible against the wire frame of the baskets.

I used an upholstery needle (green arrow points to it) and clear monofilament fishing line to secure the cocoa liner to the metal frame.

Next, I used the same fabric to cut permeable landscape fabric to a slightly smaller size as each of the cocoa liners. I held the landscape fabric in place with a couple more monofilament stitches.

After this circle was cut, I trimmed it a bit to make it slightly smaller than the cocoa liner.

Finally, filled the baskets with soil and plants. The landscape fabric allowed water through but kept the potting soil from working its way into and through the cocoa mat. The fabric slowed water enough to ensure the potting soil was soaked through but not so long that roots were soggy.
This combination of steps took time, but the basket liners lasted five years before they needed replacing. I probably could have gotten through a sixth year if I had not accidentally cut through the landscape fabric when I was digging out spent plants.

This is the fall cleanup after three years. Old plants have been pulled out. New potting soil will be poured in so that the baskets will be ready for spring planting. The hot-pink duct tape on the handle of the soil scoop helps me find it.

Triple tier planted in primary colors

Triple tier with cut Christmas greenery

If you use standard cocoa liners for hanging baskets, this effort may be beyond what you are willing to do, but if you have oversized baskets, give it a try.

Marvelous Mondo

Mondo grass (Ophiopogon, pronounced oh-fee-oh-POH-gon) has always been my preferred groundcover choice for shady areas. Less than a foot tall at maturity, it forms a thick evergreen blanket that chokes out weeds. This low-maintenance plant is hardy in zones 6-10. It is salt-tolerant, accepts limited foot traffic and will grow in any well-drained soil. Deer leave it alone.

Also known as Dwarf Lilyturf, Mondo’s white or pale lavender flowers are typically concealed by the foliage. This is unfortunate, because the flowers mature into pretty cobalt blue berries. I like to use Mondo under Crepe Myrtles because it hides their fallen leaves and will protect the Myrtle’s tender bark from damage by string trimmers or mowers.

While it is undemanding, Mondo will look best when it is grown in neutral to slightly acidic soils and irrigated during extended dry spells. The leaves are not bothered by the fungus that sometimes causes Liriope leaves to develop spots and streaks, necessitating a late winter cutback.

Black Mondo planted in a face container

Two Mondos are worth seeking. Ophiopogon planiscapus ‘Nigrescens’ is commonly called Black Mondo. The strappy leaves are truly black. They make an eye-catching addition to planters containing pink, blue, or chartreuse partners.

Crystal Falls® Ophiopogon japonicus differs from all others. Sometimes known as Giant Mondo, its leaves reach up to thirty inches in length, although they arch so much the plant height is usually about twenty-four inches. The white flowers are more evident than standard Mondo, and they produce similar metallic blue berries.

My experience with Crystal Falls® (Ophiopogon jaburan 'HOCF' PP17430) has indicated that it does not like to be divided and relocated too often. Select a location where it can spread without invading the territory of other plants. I have successfully grown it in a container, too, but after three years the roots grew so much that it broke the flimsy ceramic pot.

Use any of the Mondos as groundcovers, edger, or in containers. If used as a bed edging, its spread by underground rhizomes must be contained to restrict its reach into flower beds.

Used as a groundcover, this Giant Mondo (Crystal Falls®) will absorb the spent flowers, seed pods, and leaves shed by the Crepe Myrtle in the center of the clump.

Mondo Grass used as an edger. Photo by Jim Robbins. Used under CC BY-NC-ND 4.0

Closeup view of the brilliant blue berries of Ophiopogon. Photo by Jean. Used under CC BY-NC-ND 2.0

Sadly, the blue berries are almost concealed by the foliage. Photo by VanLap Hoang. Used under CC BY 2.0

Keep Cast Iron Containers Cool

A traditional favorite gardening container material is cast iron. Cast iron urns are beautiful and elegant, but are very heavy. Painted cast aluminum is a popular substitute because it does not rust and it is not quite as weighty.

In the deep south, the walls of metal plant containers capture heat in summer. They transfer heat to the soil within, to the detriment of the plants growing within. One way to prevent hot metal from damaging tender roots is to provide an insulation layer between the pot and the potting soil. I have tried several different strategies. The most effective insulator I have found is bubble wrap, the kind used for protecting delicate items during shipping. It is inexpensive, flexible, and malleable to fit the nooks and crannies of elaborate containers. Simply cut a piece of wrap that is large enough to line the inside of the container. Place the wrap around the outside container walls, being careful to avoid blocking any drainage holes. It is easily trimmed to size with scissors, so that there is no excess visible above the soil line. Add regular potting soil inside the bubble wrap layer, and – voila! – the soil will not become scorching hot because it is not in direct contact with the metal. The thin material does not reduce the amount of soil available to whatever plants you choose for your container.

Another tidbit: Reduce the amount of potting soil needed by large containers by adding a layer of pine cones in the bottom, before adding soil.

This iron urn is lined with bubble wrap prior to the addition of potting soil.

A green and white combination looks classy and cool, even in the heat. Container contents: Diamond Snow Euphorbia (a filler), Rosemary (a thriller), and a double Calibrachoa (a second filler). Not shown, an ivy with a white leaf edge (a spiller). The Rosemary is evergreen, so it can carry over to anchor a winter container.

The completed planting. In a couple of weeks, the Rosemary will gain height and be a vertical center accent. The strong pine-like scent of Rosemary repels some insects. I’m hoping that it will keep mosquitos away from the seating area near this container, one of a matching pair.

Container Plants and Heat

Follow a few steps to keep container plants happy during the hottest part of the summer.

First, choose plastic or composite containers rather than clay or metal. Avoid dark-colored pots. Unglazed terracotta allows rapid evaporation of soil moisture, and metal can get hot enough to damage roots. Insulate the inside walls of iron urns or cast aluminum containers with bubble wrap or several layers of newspaper to keep soil cooler. Go big rather than little. Large containers do not dry out as quickly as smaller ones, and close grouping of containers will form a protective community, reducing evaporation in each. “Self-watering” containers have a hidden reservoir that captures water, and allows overflow to be available to the container. Do not allow plants to sit permanently in saucers of water or roots will rot. Mosquitoes breed in standing water, too.

Potting soil with high organic matter will retain moisture better than low-humus soils. For years, I purchased hydrogels and added them to my container soil mix. Hydrogels were first patented by two employees of Union Carbide Company in 1967. They are crystals about the size of large grains of sugar and can hold 600 times their weight in water. When water is absorbed, they look like clear jellybeans. The theory is that they will absorb moisture (from rain or irrigation) and release it back to the roots during dry periods. However, university lab tests (Washington State University, documented by Linda Chalker-Scott – click HERE to read additional info) showed that this retained moisture is not necessarily transferred to plants. In the WSU lab, several brands of hydrogels were used in the testing. The plants were grown in 1-gallon containers and watered when the medium was less than 80% saturated. After all of the plants matured to the same size, watering was stopped and the plants were allowed to dry out. Each plant was tested at regular intervals to determine moisture content. The results showed that none of the hydrogels kept plants supplied with water any better than the plants that had nothing added to the soil. One product actually stunted the growth to the plants to which it was applied. The crystals break down in five years or so, and degrade into carcinogenic neurotoxins. Ugh! A light top-dressing of a fine-textured mulch WILL reduce evaporation. A groundcover in a container will also help keep soil cool and moist – think Creeping Jenny, Ajuga or Dianthus.

Unless they are huge, containers can be repositioned to avoid full sun exposure during periods of punishing heat. Protect pots from excessive wind. Thirsty plants may require twice daily watering in sweltering heat. Ideally, drip irrigation can run to containers, but this restricts their repositioning.

Selecting heat-tolerant and drought-tolerant specimens makes good sense. Succulents are available in different colors and forms. Most are relatively inexpensive. A single Agave or Yucca can be quite attractive. Plants with grayish foliage or wooly leaves are almost always good choices for hot spaces.

This lovely Ixora is in a plastic container which has been inserted into a decorative clay pot. The double potting provides insulation against heat and prevents excess evaporation.

Don't Discard Your Fall Mums

Long-flowering, colorful Mums are ideal for adding spots of bright color to the autumn garden. There are 30 different species in the Chrysanthemum genus, broadly categorized into “florist” mums and “hardy” mums. They are further broken down into different types of blooms: cactus, cushion, anemone form, incurved, intermediate, Korean, pom-pom, spider, reflex, single, others.

All Chrysanthemums demand full sun, rich soil, and regular water. Container specimens must have good drainage to prevent root rot. Plants have a shallow root system, and may need daily irrigation during the hottest part of the summer. Flowers come in a wide range of colors: yellow, orange, burgundy, purple, bi-colors. Good air circulation will prevent leaf issues. Plants are perennial in zones 5-9.

In garden beds, pinch plants back often in spring to keep them compact and get more blooms. Stop pinching in late June so they have time to develop bloom buds. Bud formation is triggered by the shorter days of late summer and early fall. Divide plants in spring, every two or three years, discarding the woody interior section and replanting the vigorous outer portions. Plants can be propagated from cuttings.

Potted (“florist”) Chrysanthemums are found at big box stores and grocery stores in the fall. These have been greenhouse bred and chemically treated to keep them short and light manipulated to make them bloom on cue. They are typically not as cold-hardy as the selections grown for borders. Gardeners in warmer zones can keep them in a freeze-free area through winter, then plant them out into the garden in spring. Some will survive and return the following year, but they won’t ever be compact like their original supermarket form. Plants may bloom much earlier (May or June) and be much taller (24-30”).

Chrysanthemums are toxic to humans, horses, dogs, and cats. Their pungent foliage makes them less likely to be browsed by deer or rabbits.

A Groundcover as Container Specimen

When is a groundcover not used as a live mulch? When it is a container plant, of course. Lysmachia congestiflora ‘Walkabout Sunset’ has a beautiful, multi-colored leaf and clusters of bright yellow blooms. Initially the common name, Loosestrife, frightened me away from using this plant because I feared it might be invasive. I’m happy to report that this is not the case.

Several cultivars are available. All are low growing (to six inches) and will spread readily since they root wherever stem touches soil. This spreading habit makes it a great choice for edging in-ground water features. Lysmachia is a semi-evergreen perennial in zones 7b to 9a  In my 7b garden, I find ‘Walkabout Sunset’ sheds most leaves and looks dead by late winter but makes a rapid recovery when spring arrives. It will not tolerate temperatures below 15 degrees, so I take a small cutting in autumn and overwinter it in the greenhouse as added insurance against plant loss.

‘Walkabout Sunset’ performs best in part-sun, with a little shade in the hottest part of the day. It prefers damp to wet soil and is undemanding as to soil pH. I sited a potted specimen in full sun and found that it needed more additional water than I was willing to donate, so I relocated it to the raised portion of a birdbath. This solution kept the plant roots damp and gave birds and insects a place to perch when they visited the water source. Everyone was happy.

‘Walkabout Sunset’ is equally attractive when used as a sole container specimen or as an undercover to a taller plant. The variegated leaves have a blue-green stripe that pairs well with a similarly toned container.

You will note that I did not include the pronunciation above, as I normally do. Here goes: ly-si-MAK-ee-uh kon-jes-tih-FLOR-uh. I have observed that some well-known plant experts pronounce the third syllable with a long A while other make it a short A. I thought it would be easier to stick with the cultivar name, but then I found some plants tagged as ‘Walkabout Sunset’ and others as ‘Outback Sunset’ or ‘Waikiki Sunset.’ Are they the same? I cannot tell. What I can tell is that ‘Persian Chocolate’ has purple-ish foliage. Can’t wait to try it in a container with pink Begonias.

Foliage color mirrors container

Birdbath keeps soil wet

Heuchera for Year-Round Beauty

When the winter garden is clothed in dormant twigs and fallen leaves, a touch of lively color lifts the spirit and reminds us that spring lurks ahead. Heuchera is a colorful group of perennials that are hardy from zones 4 to 9, depending upon variety and lineage. Modern cultivars have parents in H. villosa and H. americana. In the south, Heucheras (common names: Coral Bell, Alumroot) withstand hot and cold temperatures and look good every month of the year. Tiny blooms, a favorite of butterflies, are held atop wiry stems, but Heucheras are grown for their outstanding foliage. Cultivars have caramel, rose, lime, purple or green leaves marked with silver, red or white.

The lovely chartreuse green ‘Citronelle’ is one of the most heat tolerant cultivars. Grow it in shade to partial shade, where the leaves will be more yellow than green. Full sun leads to crispy edges and bleached leaves. I planted dozens of these in a lightly shaded bed. Within three years, there was only a single survivor. Each one got smaller and smaller, dwindling down to a single leaf before disappearing completely. I finally discovered the key to success – well-drained soil. The native heavy clay soil of upstate South Carolina mandated container culture, enhanced by fertile, well-drained potting soil and frequent watering. I plucked the lone ‘Citronelle’ specimen from the ground and placed it in a container with two other Heucheras, a purple-leaf variety (lost the cultivar name) and ‘Caramel,’ with caramel-colored leaves. Instant success! I eventually moved ‘Citronelle’ to her own container and replaced her with ‘Key Lime Rickey.’ These three live shoulder-to-shoulder in a container which looks as good in February as in August. Two ‘Amber Waves’ plants look especially good in a pair of peachy-toned clay pots along a brick walkway. These are sited in full sun. (Evidently, they did not receive the notification that they were meant for shade.)

A trio of Heucheras (‘Caramel,’ ‘Key Lime Rickey,’ and an unidentified purple leaf cultivar). These three live in harmony all year long. The container looks this good even in winter.

Plant breeders introduce new cultivars every year, with an ever-broadening range of color and vein combinations. One thing I have learned about this wonderful plant: Catalog photos are taken when plants are at their very peak of beauty. Plants that exhibit gorgeous apricot and rose shades in spring (such as ‘Sweet Tea’ or ‘Peach Flambe’) may mature darker, even dirty-looking by August or September. My beloved ‘Berry Smoothie’ is raspberry-rose in spring but darkens to purple in winter. In catalogs, ‘Stop Light,’ is a beauty, with yellow-lime leaves marked with bright red veins. I have never been able to replicate the distinctive markings in my garden and had to settle for a red vein here and there. Purple-leaf forms age a bit better. ‘Obsidian’ is almost black. It looks especially good in containers with pink Begonias or Caladiums. Heucheras also pair well with smaller grasses, such as Lagurus ovatus ‘Bunny Tails.’

If a mature Heuchera develops an elongated stem, it is time to lift it and replant it to position the woody section under soil level. Remove tattered or crispy leaves at any time to keep the plant looking tidy. Heucheras are rarely browsed by deer or rabbits.

Finally, Heuchera is pronounced HEW-ker-ah. This one is mispronounced even more than Liriope. The first syllable rhymes with Yew. Get it right and you have risen to the upper echelon of gardeners.

'Amber Waves' ruffled, peachy leaves

'Berry Smoothie' plum and silver leaves