February 28, 2012

Cattleya Orchids for
Landscape Culture

BL. Morning Glory
one of the best and most vigorous
hybrids for outdoor culture
One of the many advantages to living in Miami is the ability to use orchids and other epiphytes as permanent landscaping. I've written about the myriad uses of such plants in previous blogs, but here I will focus on a certain group of orchids well suited for landscape usage. There are numerous Cattleya-alliance hybrids which are great candidates for landscape applications, including Broughtonia, , Brassavola, Laelia, Diacrium, and Schomburgkia hybrids. The range of flower colors and plant sizes is enormous, and the prices have dropped nicely so that plants can be purchased most reasonably. Our local orchid sales are well stocked with such vigorous hybrids, and most of the plants flower several times per year. Numerous inter-generic hybrids are available as well, in a huge range of plant sizes. There are hybrids using the petite Brassavola nodosa produce carpets of foliage with modest roots, 3 inch flower spikes, small, brilliant flowers, and a near-continuous flowering habit. Hybrids using Schomburgkia as a parent tend to be large, heavy, robust plants with 2 to 6 foot long long flower spikes, and flashy flowers with good coloration. 


Laelia purpurata
the glorious species from Brazil
with over 500 known color forms.
It is one of the parents of Bl. Morning Glory 
There are species and hybrids for cool climates such as coastal California and those for tropical conditions, as seen in the Florida Keys.

What makes a plant suitable for tree culture, or use in the landscape ? The qualities that make a good "tree" candidate are plants which naturally grow in sunny locations on exposed trees, which qualities exclude many terrestrial genera. A great many species in the genera listed above make excellent choices for landscaping applications.   
Some research with local growers will yield information about which orchids like to grow as mounted specimens or in baskets. These plants will also make good landscape plants, provided they get routine watering and fertilizing. Increasingly I see good quality orchid plants for sale at home improvement stores' garden centers.     

Schomburgkia tibicinis x
Cattleya forbesii 

Cattleya skinneri
'Heiti Jacobs' FCC/AOS

Iwanagara Apple Blossom
courtesy of Carter and Holmes
an outstanding repeat-blooming type
Dialaelia Mizoguchi
great for outdoor or basket culture

One of the criteria which determines which plants can be grown on a given type of tree is whether the plants has ascending rhizomes or grows in a flat plane. The ascending-rhizome types, as seen in the Laelia anceps parentage, are great for growing up an angled branch. The flat-rhizome growers, as seen in the Brassavola nodosa and many repeat-flowering Cattleya alliance types, are good for growing on tree trunks or horizontal tree branches. Whichever type you use, give the plants at least 3 or 4 hours of direct morning sunlight. Too much shade will net you a lush plant with few flowers. Try a few different plant types to see what grows best for you, consult some local orchid growers for their ideas, and experience the easy care of established orchids on a natural mount. Once you get proficient at it, you'll wonder how you ever spent so much money of expensive orchid potting mixes and fancy pots !

Craig Morell
Pinecrest Gardens


February 14, 2012

Thoughts on Organic Fertilizers

We hear a great deal about "organic fertilizers" in just about every type of media outlet. There are lots of articles, magazines, books, videos, and societies about organic fertilizing. The idea of organic fertilizer is somewhat more of an integrated garden  lifestyle than a science, although there is plenty of science involved, just not the sort we're used to seeing on most fertilizer containers. Let me cast a bit of light on the ideas of organic versus synthetic fertilizers.

a serious punch of

On most synthetic fertilizers, we'll see the ingredients listed as we would see on a food container: the primary ingredients are listed in order of their occurrence.There are guaranteed percentages of ingredients like urea, ammonium phosphate, potassium nitrate, and so on. There are secondary ingredients such as iron and manganese compounds, copper, boron, and so forth. The components are listed in precise percentages, and with many commercial products, you get a guaranteed and predictable product, batch after batch. 

There is a growing resistance to using synthetic fertilizers on food crops, and many rose growers will prefer to use organic fertilizers rather than synthetic ones. Why would plants prefer one type of fertilizer over another ? Why would people prefer to use one product over another ? 

Organic fertilizers are made from natural materials, in most cases. The myths are that organic fertilizers are "better" for the plants, safer for the Earth, and won't burn plants or pollute the environment. In many cases this is true, but there are some serious misunderstandings in the widespread use of organic fertilizers. In the first place, we need to better understand what the needs of plants are to be able to fertilize them well. A good example is the use of manure as an organic fertilizer.

one of the few sources
of organic potassium

It is very common for people to use manure as a garden soil, not understanding that many plants won't react well to the high urea-nitrogen content.  Manure also lacks phosphorous or potassium. Adding lime or bone meal to manure solves one of the missing ingredients, but potassium is still lacking. Adding greensand or muriate of potash makes a more complete fertilizer, but you have an expensive, albeit organic, fertilizer. Any single component of organic fertilizer affects a stage of growth, and the real key to successful organic fertilizing is to use a complete fertilizer, satisfying the plants' needs for nitrogen (N), phosphorous (P), and potassium(K). Many bulb plants need more P than N, yet richly organic soils will promote foliage growth more so than solid roots and bulb formation. 
Roses need a greater amount of  P and K to produce good blooms, whereas Canna lilies need more N than P to produce the green stems that produce the flower heads. 

a good choice for an all-purpose
organic fertilizer
 The main issue at hand is to understand the fertilizers and how they make plants react. Simply stating that organic fertilizer is safer for the environment and more usable by plants is a mistake. Millions of tons of manure are generated by the ranching industry. Applying these mega-tons of manure near lake or river watersheds will certainly pollute them during heavy rains. Plants will grow quickly with manure applications, but will likely have a poor fruit set and poor root systems. Many organic fertilizers are good components of an integrated fertilizer program rather than as a single component.    

                                                            Not all organic products are safe for plants at all levels. Lime is an organic ingredient, yet in the wrong place it may raise the pH of soil to hazardous levels. Blood Meal, a favorite of rose growers, can burn plant roots when used too often or at high rates. It also smells terrible, as do some other organic fertilizers. Muriate of potash or even wood ash can burn plant roots when misused, or without integration into a program of soil enrichment. High phosphate levels can tie up other fertilizer components, especially metals like iron and manganese. Any fertilizer is risky when it is misused. I believe the true issues to talk about are the amount of energy input required to make synthetic fertilizers, and the proper use of any fertilizer, organic or otherwise.

Organic materials can work wonders, if you know how to use them. People need to understand the complexities of organic fertilizers before they can be used to their full potential. It may be several times more expensive to use organic materials than the synthetic ones, but the plants may grow better, with less pollution and less energy required to produce them.

an old stand-by product,
a favorite of organic and rose growers alike
 Once again, I make a pitch to understand the techniques employed in growing plants. There is a lot of emotion being generated about "going green" and buying organic food. I ask that people do some research to check out what the true meanings of the terms are, before we pay too much attention to the "green" gardening furor.

Craig Morell
Pinecrest Gardens                     

February 7, 2012

Bromelius Retailicus

NOT a garden type of bromeliad !
(Guzmania conifera)

In recent years, bromeliads of several types have shown up at garden centers and big-box home improvement stores. The array of colors and sizes is impressive, ranging from small plants in 2 inch pots to yard-diameter monsters in 14 inch tubs. Most of the plants, however, are in 6 inch pots, and are soft-leaf types with colorful and long lasting flower spikes. These are, for lack of a better term, "retail bromeliads", and I have Latinized the farcical general name into the title above. 

commercial Vriesia hybrid

What should you do after you buy one of these plants ? It is best to keep the plants away from strong sunlight, and in warm, humid conditions. A well-diffused bright and shadow-free light is ideal. Kitchens and bathrooms make ideal greenhouses in much of the USA in winter. The plants are usually grown in pure peat moss which holds a lot of water, but the plants don't need to be soaking wet to grow well. It is recommended to keep water in the center of the plants, but the roots should be moist also. The best way to water the plants is to pour room-temperature water into the center of the plant until it flows into the lower leaves , into the roots and out the bottom of the pot. Make sure that the pot has holes in the bottom of it, or the plant will quickly suffocate.  

Once the plants have been thoroughly soaked, wait until the surface of the potting medium is almost dry and then water thoroughly. Do not allow the soil to become very dry; it is difficult to re-wet the medium and it may take 4 or 5 or 6 attempts to get water to penetrate the center of the dry root ball. The plants are fairly light feeders at this stage of their life, but if you choose to grow the plant after it flowers, then it will need to be repotted and fertilized regularly. 

Guzmania 'Graaf van Horn'
a large plant, to 1 meter across

Once the plant has finished flowering, it can be grown as a houseplant like any other bromeliad suitable for houseplant culture, but most are not suitable for in-ground outdoor landscape culture. After flowering, cut off the old flower stem, remove as much of the old peat moss as possible, and repot the plant into a mixture of equal parts of African Violet soil and perlite.

Osmocote or Dynamite or any other controlled release fertilizer should be mixed into the potting mix, and the newly potted plant can be grown inside in a bright window sill or bright spot in the garden as a potted plant. It will take 18-24 months for the new offshoots to grow into a plant large enough to flower.  Most of the hybrids grown for retail sale are not very good as landscape plants in the ground, but are excellent as hanging basket plants or potted plants in protected locations. These plants are meant to grow fast in the nursery, have great colors, last a long time on the garden center shelves, and then essentially become disposable. With extra care they can make nice outdoor plants. There are great bromeliad choices for the landscape. Most of the "bromelius retailicus" types are meant for a different lifestyle, other than in the ground. 

Craig Morell
Pinecrest Gardens 

February 1, 2012

Sterilizing Cutting Tools

sterilize cutting tools by heat;
old-fashioned, but still effective

One of the perennial problems in gardening is how to clean gardening tools after using them, especially cutting tools. Dirty cutting tools can spread diseases quickly, but how do you sterilize something that's full of dirt ? There are some time-tested ways to do the job, especially necessary with disease-prone orchids. In most instances, you don't really have to sterilize a shovel or an ax.  Many soft-tissue tropical plants, though, can contract a number of diseases spread by cutting tools. It is usually wise to sterilize cutting tools when cutting into orchids or members of the Aroid family. Some fairly recent ( and lethal on a large scale) diseases such as Texas Phoenix Palm Decline, Laurel Wilt and Sudden Oak Death can be readily transmitted by cutting tools.

useful, but very corrosive to tools !

In the home garden, cleaning hand tools is easy. For decades, orchid growers have sterilized their pruners and knives with a range of products, but I prefer to use either heat from a propane torch or to soak tools in a TSP ( trisodium phosphate) solution  to sterilize tools. Either technique will nicely rid your tools of any pathogens that may harm your plants. The disadvantage to using high heat is that you will discolor tools, and possibly ruin their smooth finish after repeated heatings.  TSP is hard to find in some states with regulations about phosphorous, but it is sometimes available in paint-supply stores to use for cleaning walls before painting them. It will retard rust or corrosion, and leaves no residue on the tools.  

useful, and will not corrode tools

To sterilize larger tools such as shovels, saws, and loppers, wash them off with a garden hose after using, and dip them in TSP or germicidal soap solutions.  Rinse off the soap, then spray the tool heads with light oil to keep them from rusting. Disease transmission in plants is a larger issue than people may realize, and in some cases, a single cut into a clean plant can infect it if the tool was previously used on an infected plant. Some bacteria and several fungi can rapidly infect a plant, sometimes within hours of transmission into a cut surface. 

Virus Infection in Phalaenopsis

Virus Infection  in
Cattleya Orchid
Orchid growers need to be especially careful about virus and other pathogen transfer from plant to plant via cutting tools. Orchids are among the most disease-sensitive of commercially grown plants. Repotting orchids calls for the greatest degree of sterilization with cutting tools. While many orchids are very disease-resistant, some are especially prone to get diseased, especially in intensive greenhouse or high-density growing conditions. It is common to see growers grow their plants with high density vertical stacking, hanging one plant underneath another, underneath another. In some cases I have seen 12 plants strung together in a column. If the plant on top of this column of plants becomes diseased or infected, it can infect the entire column in a matter of days. This is a very expensive loss ! 

Erwinia Bacterial Infection in
Calla Lily
One of the most productive tactics to employ when cutting into plants is to use a sterilized cutting tool, and keep 3 or more cutting tools clean and ready to use. When you finish cutting into a plant, set the used cutter aside, and use the next tool in the line. When you get to the last clean tool, re-sterilize the group, of tools and start anew. This chain-of-use system is easy once you get used to it, and can save a lot of plants from becoming infected. This method becomes an automatic part of your skill set when working with certain plants. If you know that certain garden plants are are susceptible to cutting-transmitted diseases, it is easy enough to heat-sterilize a shovel or ax or blade with a propane torch. It may sound like a lot of trouble, but these tactics only take a few seconds, possibly saving a plant in the process.    
Craig Morell
Pinecrest Gardens