Saturday
Mar142015

How to Plant and Care For Azaleas

One spring we visited Calloway Gardens in Pine Mountain, Georgia just as the azaleas were at their peak.I have never forgotten the swaths of candy colored shrubs that blanketed the woodlands. Since then I have dreamed of a similar effect in my own garden, although on a much smaller scale! 

I am speaking of azaleas in this post, but the planting and care of rhododendrons is very similar. Azaleas and rhododendrons are all in the genus Rhododendron, with thousands of named selections. All azaleas are rhododendrons, but not all rhododendrons are azaleas! It is fairly easy to tell the difference. Generally, rhododendrons have much larger, leathery leaves. Many rhododendrons will not grow well in the sub-tropical southeastern US, while azaleas, which love warm air and humidity, can flourish here as well as in the Middle and Upper South. Depending on the variety, azaleas will grow in hardiness zones 5-8.Azaleas blooming April, 2014 in my front garden

While iconic images of the Deep South often include azaleas, these plants are not necessarily easy to grow. The secret is site selection and planting. Choose a site that receives morning sun and afternoon shade. Too much sun will make azaleas susceptible to lace bugs. Too much shade will cause lanky growth and decreased flower production. Filtered light under tall pine and oak trees is ideal. Do not plant near shallow rooted trees such as maple trees, which will compete for moisture and nutrients. Azaleas also need acidic soil with a pH of somewhere between 4.5 and 6. 

Moist, well-drained soil is an absolute requirement for all azaleas. If one sticks an azalea in unimproved clay soil, it will die. Azaleas have shallow, delicate roots, and they must have friable soil in order to spread out to seek nutrients and water. These fine roots will drown in standing water, and they also will quickly smother in hard, compacted soil. Poorly drained soil will also promote die-back due to soil-borne fungus.

Like many gardeners in my area, I have clay soil. There are two solutions to this problem. Probably the easiest thing to do is to build a berm or raised bed about 8 to 12 inches high. Fill the bed with 50 percent good garden soil and 50 percent organic matter such as pine bark, peat moss, compost or chopped up oak leaves. Plant the azalea high with about two inches of its root ball above ground. Then pull the improved soil up around the top of the root ball. Mulch with pine bark or pine needles. The mulch will conserve moisture and help keep the shallow roots cool during the hot summer. Kurume azalea 'Snow' grows in my front garden.

To plant directly in the ground, dig a hole at least a foot deep and about three times as wide as the root ball. Fill the lower half of the hole with a mixture of 50 percent native soil and 50 percent organic matter. Place the azalea so that about two inches of its root ball is above ground. Then fill the remainder of the hole with organic matter. Pull the organic matter up around the root ball and mulch with pine bark or pine needles. 

Be sure to loosen the roots and water the azalea before planting. If root bound, use a sharp knife to make several vertical cuts around the perimeter of the root ball. Then gently loosen the roots as much as possible.

Once planted, slowly and thoroughly water. Continue to water the azalea two or three times a week until the roots are well-established. This is why I like to plant azaleas (and most everything else) in the fall. I rarely have to water them once our winter rains begin. Our soil does not freeze, so the roots have winter and spring to establish themselves before the stressful heat of summer arrives. Azaleas need consistent moisture, about one inch of rain per week during the hot summer. If nature doesn't provide it, the gardener must. But remember: too much water can be just as harmful as too little! Azaleas will absorb water through their leaves, as well as their roots, so overhead watering is beneficial. It is best to water in the morning so the leaves dry by afternoon. Damp leaves in the evening hours can promote growth of fungus.

Azaleas in rich, acid soil need little or no fertilizing. If the pH of the soil is too high, the leaves will demonstrate chlorosis, or yellowing. If needed, cottonseed meal or a fertilizer for acid-loving plants should be applied after flowering has finished in the spring. 

Azaleas are more attractive if allowed to grow in their natural shape, rather than sheared into tight balls, which is the habit of many who plant these as foundation shrubs.The brilliant orange Kurume azalea on the right has been growing in my garden for many years. At about four feet tall, it needs minimal pruning.To avoid cutting off next year's blooms, lightly prune by snipping off spent flower stalks in spring just after blooming has ended. This is also a good time to apply fresh mulch. Azaleas can be rejuvenated by drastic pruning, down as far as one foot of the ground. Do this in late winter or early spring, but remember you will lose the spring blooms. 

Both adult lace bugs and their immature form, called nymphs, damage azaleas by sucking sap from leaves. Leaves develop a grayish cast with a speckled or stippled appearance. If damage is severe, the leaf will appear white and will drop early. The insects feed on the underside of the leaves, so close inspection of the underside will reveal shiny black bits of insect droppings. I thoroughly spray my azaleas with horticultural oil, five tablespoons per gallon of water, in early spring as a preventative against these and other insects that may afflict azaleas. If harmful insect populations are allowed to grow, stronger insecticides may be required.

Azaleas attract butterflies and other pollinators.A butterfly enjoys the nectar from my 'George L.Taber' azalea, a Southern Indica Hybrid.Some grow low to the ground, and some will grow up to 25 feet. Choices include exotic evergreen azaleas and native deciduous azaleas.These native azaleas are growing at John's Native Gardens near Scottsboro, Alabama. Their willowy, upright forms look best in a natural setting.By choosing different varieties, one can have azaleas blooming from spring through fall. If well-planted and cared-for, these beautiful shrubs will return the investment many times over. The deciduous native azalea 'Florida Flame' has glowing orange blooms that light up my woodland garden in April.

Saturday
Mar072015

My Voodoo Lily is Blooming!

One day toward the end of January I innocently opened my pantry door, and a coiled snake was staring me in the face. 

My startled gasp had barely escaped my lips and my heart had not recovered its normal rhythm, when I realized it was not a snake at all. It was my Amorphophallus konjac, AKA voodoo plant, snake lily, devil's tongue and corpse plant. All of these names are appropriate.

This is what happened: Back in the fall I had dug up the tubers of my two voodoo lilies, which live in pots out in the garden through spring and summer. After brushing the dirt off the tubers, I put them in a sack and placed them on a shelf in my pantry, with plans to replant them when new growth began in the spring. 

My excuse for owning these plants is that I did not know what I was doing when I bought them; and once I had them, it was too late. For the full story, read my old post Under the Spell of the Voodoo Plant. When I first acquired them in 2010, my voodoo plant tubers were tiny, the largest being only about the size of an almond. It takes about five years for these plants to grow to blooming size. The largest one was almost four inches across when I dug it last fall, and 2015 would be its fifth year; so I was expecting it to bloom this spring.

This is what the larger voodoo plant looked like after I rescued it from the pantry shelf. The tuber is almost four inches across. Note how wide the stalk is as it emerges.I thought the smaller one, which was about an inch smaller, could need another year.

Notice I said I thought it would bloom this spring. The reason the plant is called corpse plant is because the flower is said to smell exactly like rotting flesh. (Surely that was an exaggeration!) Because it would be out in the garden when it bloomed, I was not concerned.

The plant decided to surprise me. The smaller tuber sent up a slender stalk, which poked a hole through the plastic sack and then grew upward until it encountered the bottom of the shelf above it. It then turned sideways and reached the cabinet door, which I am sure it would have pushed open if I had not first opened it myself.

I stared in amazement at this thing. There was a swelling at the end of the coiled, spotted stalk, which could easily be interpreted as the head of a snake. I realized the plant was going to bloom.

In February. Inside my house. Oh, no.

Upon research, I discovered that Amorphophallus konjac sends up its bloom in late winter to early spring. So my plants were right on time. I untangled the tuber from the plastic sack. The larger tuber was also pushing up a stalk. It was shorter but much thicker than the other one. It was going to bloom, too.

This photo was taken February 1, about a week after I took the voodoo plants out of the pantry. The smaller tuber is still leaning dramatically to one side, but it has begun to straighten.

I transferred the tubers to a pot, and I watched anxiously as both plants grew rapidly. With space and light, the little one soon straightened itself. Its inflorescence unfurled by the second week of February.

February 7. The first bloom! Our cat Autumn checks out the smell.Powerful enough to bring tears to my eyes, the bloom had the stench of a very bad crime scene. Fortunately, we had a few warm days while it was blooming, so I was able to sit it outside during the day. We were amazed by how many tiny flies came to the plant, hunting for food but being cruelly tricked even as they did their part in pollination. At night I brought the plant inside and put it in the back part of the house where our cat Autumn stays. I made sure the door was firmly shut between that area and the main part of the house. I am not sure how Autumn felt about this arrangement. After one whiff, she kept away from the plant.

The stink persisted about a week, and then after a couple of weeks the bloom began to decline. Meanwhile, the larger plant was growing to about three feet tall with a stalk over an inch thick. Now, a month after the small one bloomed, the larger one has opened its cobra-like hood.Strange and beautiful! In the lower right image, one can see remnants of the first bloom, to the right of the stalk.

The weather, which has been freezing this week, warmed up today and will stay mild. Outside the voodoo plant goes! By the time it has finished blooming, it will be time to plant these weird plants in their summer pots. In a month or so they will send up unusual, umbrella-like leaves, which will add an exotic note to the garden.

My plants are young. In coming years the tubers could grow to a foot in diameter and send up stalks nearly six feet tall. Amorphophallus konjac is stunning in every way. What do you think? Would you forgive the stench?