January 21, 2011

Pendant Dendrobium Culture

Dendrobium superbum ( anosmum)
different color forms

Dendrobium pierardii

Quite a lot of  people have read the blog about pendant Dendrobiums , so I decided to expand on the culture of the group. In most cases, these plants are grown in baskets or on mounts made of treefern fiber or cork with a thick pad of sphagnum moss attached to it. The canes can hang down on some species from the mount as much as 9 feet, so give the canes plenty of room to grow !

As these pictures illustrate, the plants grow mounted, and not potted. This mandates a regular watering and fertilizing schedule while plants are in active growth. The very best flowering I've seen on this group of plants has been with plants watered daily, and fertilized every week or even more often. In this group of plants, if the roots never get dry, and the plants have an abundant supply of fertilizer, the canes will grow to their maximum dimensions.

Once the canes have matured, indicated by the cessation of new leaf growth, ( usually in November-December) then STOP WATERING the plant, and STOP FERTILIZING the plant. Water the plants enough to keep the canes from shriveling. If you water this group of plants while they try to go dormant, then they'll start growing again, and you will lose most of the flowers. This is a natural cycle for the plant, since so many of them come from monsoon-drought climates. The plants are used to being soaked by heavy tropical rains every day for several hours, week after week. When the monsoons end, there is little rain for weeks on end, sometimes no rain at all for months. The plants use this rest period to build flower buds, which burst forth in mid-Spring to Summer to attract pollinators when the rains arrive anew. While the plants have a fairly short flower life, they are usually quite flashy, and often have heavenly fragrances. One of my personal favorites is Den. parishii, a petite species that would spend its life in an 8 inch basket. It has a rich fragrance with a hint of cloves  

Dendrobium parishii

Dendrobium fimbriatum var. oculatum
a hefty grower, canes to 8 feet or more

Dendrobium wardianum
a Himalayan species

Many species can be accommodated  in wood or plastic baskets in a potting mix of fir bark or coconut chunks plus an inorganic material such as fired ceramic pellets, lava rock, or coarse perlite. The mix should hold water but still drain well. Although the plants can be mounted on trees, make sure the tree can withstand the care you give the orchid ! Some trees, such as citrus and many fruit trees don't like the copious fertilizing and watering the orchids may require. In most cases, a well-fertilized orchid plant allowed to rest in the winter will flower well the following Spring. Some growers use a higher nitrogen fertilizer when the plant is actively growing, then switch to a higher phosphorous fertilizer in early Fall to promote flowers and "slow" the plant down for a winter rest.

Given some extra attention to watering and fertilizing in the Summer, then extra care in neglecting the plant in the Winter, these plants flower beautifully. There are species in every size range and for almost every climate. The plants are easily available through  mail order nurseries, as well as local orchid shows. Do a bit of research on the plants you choose, and you'll be rewarded with some of the most beautiful and crystalline flowers in the orchid world.

Craig Morell
Pinecrest Gardens  


January 14, 2011

Amaryllis or Hippeastrum ? 

Amaryllis have been in cultivation for decades, perhaps centuries. Modern taxonomy has actually spilt the names Amaryllis and Hippeastrum into separate genera. The time-honored Christmas Amaryllis lily we see so often in bulb catalogs and at retail stores is actually a Hippeastrum, not a true Amaryllis . The actual Amaryllis is a more subtropical / Mediterranean growing bulb, and one of the best examples has been the Naked Lady group, Amaryllis belladonna. These are very easy to grow, just not in wet Florida. The plants like a coolish rest in winter, and fairly dry summers, not what Florida has to offer !!

Amaryllis belladonna
the "Real" Amaryllis
aka Naked lady Lily

Amaryllis belladonna
without foliage, therefore 'Naked Lily'

Hippeastrum papilio
The Butterfly Lily

Hippeastrum johnsonii

Dutch Hippeastrum hybrids
The Christmas Amaryllis

Hippeastrum blumenavianum

Hippeastrum Gilmar

Hippeastrum traubii

Of more interest to Florida gardeners has been the "other" Amaryllis groups, properly called Hippeastrum.
These are fairly common landscape plants in coastal Gulf states, Florida, and many parts of California. Easy to grow, in a wide range of colors and sizes, and easily propagated by seed or division, these plants are curiously not as common as once seen. I wondered why, and have not gotten any solid answers from any grower I know of. Perhaps the limited range of colors 20 or 30 years ago dissuaded people from growing these flashy and sturdy plants. The major downside to this line of plants is their relatively short flowering season, lasting 2-4 weeks. The newer hybrids have longer lasting flowers in some dazzling patterns and colors.

Dr. Alan Meerow at the USDA-Agricultural Research Service ( ARS) station at Chapman Field in Miami has been working with Hippeastrum breeding and genetics for over 20 years. He has grown many generations of colorful hybrids well suited for our climate, and has generated several hybrid lines for propagation to the nursery trade. It will be interesting to see the responses to the plants within the nursery trade.

The venerable 'Christmas Amaryllis' which we see so often in retail garden centers has been chilled to induce it to flower in the short days of the year. Naturally, these plants flower going into summer, so don't be too surprised if you plant your Christmas gift plants, and they grow to hefty dimensions, then flower "off season" in May. The plants are easy enough to grow, but most Hippeastrums suffer from mites, aphids, and thrips. These pests are easily controlled with a short series of weekly sprays of any botanical or organic pesticide. Their diet is easy enough to provide, but in most soils, an extra addition of a cup of bone meal and a half-cup of a slow release fertilizer such as Dynamite or Osmocote mixed into the planting soil will yield a solid plant. Let the plants go dormant in winter, and many of them will lose most or all of their leaves. This scheduled rest period allows the plants to switch their energy away from growing into flowering.

There are several robust species which do well in gardens, and a number of heritage hybrids that deserve more space in gardens than we see today. A good sunny spot with at least 4 hours of direct morning sunlight and well-drained fertile soil are good starts to growing these plants effectively. Start with a few bulbs in a pot, let the plants become quite potbound to help them produce maximum flowers, then plant the bulb cluster into the landscape. many species and primary hybrids produce lots of viable seed, and the seedlings are fast growing. It's fun to see the differences in the children produced from your growing efforts, equally fun to give the seedlings to friends and neighbors for their gardens, too.

At Pinecrest Gardens, we're trialing a dozen or so basic hybrids created by my friend Mike McCaffery in Gainesville, Florida. I have the long growing season that he lacks in his area, so he makes the hybrids, and I can grow the seedlings to flowering rather fast. Some of the results are really encouraging, and I hope we can distribute some of the 3rd and 4th generation seedlings to local residents. I encourage anyone with an adventurous spirit and some extra gardening space to try a few 'Hipps' in their garden. You may discover what many of us have known for decades; that some of these old standby plants are still worth growing.   

Craig Morell
Pinecrest Gardens


January 6, 2011

And Now for Something Completely Different......
Orchid Cacti !

Previous blogs have dealt with plant groups, as opposed to a specific genus. In this installation, I'll cover one of the more bewitching genera of plants, Epiphyllum the Orchid Cactus, usually a night blooming genus. At some point or another, almost anywhere in the country, gardeners will eventually see one of these in a garden window, at a plant show, or at a garden conservatory. In some southern Florida, southern Texas, and south-coastal parts of California, orchid cacti can be grown outdoors easily. The plants thrive in the cool winters of coastal  California, and of course there is an Epiphyllum Society to boost the popularity of the plants. There is a dazzling array of colors and sizes ( a familiar theme in my blogs, but it is true) and a fairly recent introduction of day-flowering orchid cacti. The plants will not likely win any beauty contests for pretty foliage, but the flowers compensate for the homely foliage. 

 Orchid cacti are completely New World plants, mostly hailing from Central America as tree-dwelling plants in seasonal rainforest or scrub areas. They like bright light, but not blazing sunshine. In Miami we can mount the plants into the dry leaf bases of palmetto palms and they grow quite well. They can also grow to sizable dimensions in hanging pots or baskets of a fine grained orchid mix. The stems grow up, then often arch down. Left to their own devices, the plants can have stems to 6 or 8 or even 10 feet tall / long. In coastal areas, I've seen orchid cacti grown in ground beds of clay and humus and sand. In Santa Monica, California, I saw them grown as hedge plants separating homes. Unquestionably, this choice of hedge plant had the most attractive and complicated flowers of any hedge plant I know !

As we have seen so often in plant groups, there are sizes and growth speeds and flower colors to suit many tastes. The plants can be grown as shade house plants in moderate climes, and as houseplants in colder climates. All that is required is to keep them well watered while in active growth and let them dry off substantially when growth stops.  

It is easy to see the allure of these tree-dwelling cactus analogs to water lilies. If you have the luxury of having shallow ponds, you can grow water lilies easily, but of not, then orchid cacti may be the next best thing, especially since they can be grown indoors anywhere ! Orchid cacti propagate readily by stem cuttings  6 to 12 inches in length, and rooted in a loose, open mix used for cacti. Many growers use a mix of 60% perlite and 40 % coarse peat moss, or even very fine orchid bark. Most growers I've seen use deep 6 inch or 8 inch pots, with at least a few inches of drainage material in the bottom of the pot. Fertilize at 1/4 strength every few weeks while the plant is actively growing. Cacti seem especially fond of organic fertilizers, and once again, rose fertilizers containing bone meal and superphosphate are helpful. 

The Internet is well stocked with vendors and information about Epiphyllums, and I encourage anyone with sufficient space to grow a pendant, spineless cactus with 3 or 4 foot stems to try a few orchid cacti. When the plants bloom, you'll be hooked, and will discover a whole new world of color and texture, in a world of plants that are so often misunderstood. 

Craig Morell
Pinecrest Gardens   

January 5, 2011

Those Beautiful, Tempting, Devilish Flowering Vines
Part 3- Slower Growers

Mandevilla amabilis
 Parts 1 and 2 of this series dealt with flowering vines, covering fast and moderate types. This installation deals with "slower" growers, which in some cases are actually vining shrubs. The speed factor of vine growth is very relative to cultural conditions in addition to the innate ability of the vine species. In other words, resource availability can make a big difference in growth speed. 
One case in point is a popular container species, Mandevilla amabilis , often sold in flower for its rich candy-pink flowers. In a container with a trellis, the plant is well behaved, with a modest growth speed. Set into sandy organic soil in the ground, the plant can grow a foot a day or more. Growers of Bonsai know this principle very well; plant a Bonsai tree, treat it as a landscape plant, and the tree grows rather fast. On the other hand, I doubt that anything would slow down a Stictocardia beraviensis except for killing cold weather.

With these words in mind, there are some species of "slower" growth in almost all circumstances. One of the interesting scenarios is that ill-determined area of vining shrubs, many of which make outstanding arbor or trellis specimens. One of my favorites is Bauhinia grandidieri, a low, prostrate shrub that will clamber over a trellis or support. It has petite light lavender flowers, prunes nicely, and grows at a stately speed without ever getting out of hand. Bauhinia galpinii with red-orange flowers, is also a clambering type of shrub, and there are several recent Bauhinia vine introductions from Thailand of  gold and yellow-flowered species.   

Bauhinia grandidieri

Bauhinia kockiana

Bauhinia galpinii

Hoya bella

Hoya macgillivrayi

Bauhinia galpinii

Defining a vine can be difficult. There are, as with so many plants, numerous groups within the term. For instance, Bougainvillea can be classified as either a scrambling bush or a "vine". One of the older definitions of a vine is a plant which climbs against upward gravity by means of spines, tendrils, holdfasts or other means of gripping a mounting surface. Ficus repens, the Climbing Ficus, makes an excellent wall cover or groundcover, but won't do very well as a draping species on a trellis or arbor. For our purposes here, I'm considering those flowering plants which actively grow upward, and will make a nice arbor or trellis. There are numerous varieties in each group, so research species carefully. Many Hoya species are very slow-growing, and there is a huge range in flower sizes, as well as leaf size and flower colors. The giant species called 'Big Mac' , Hoya macgillivrayi , can produce a flower head the size of a football, each flower as large as a silver dollar.

Beaumontia grandiflora
Easter Lily Vine
Flowering vines are a major source of character and color in a garden, whether it is a container garden in San Francisco or a public garden in Georgia, or covering a fence in Miami. There are options for choices of plant, site, and purpose. Use your local intellectual options for making the right choice, and understand what might happen if you don't.

Craig Morell
Pinecrest Gardens