Root Pruning

Click to enlarge. This photo may have given some readers the shudders. Many "houseplant" caretakers in particular are reluctant to prune their plants. They often anthropomorphize them, meaning they attribute human qualities to plants.

Scientifically this is nonsense but often a maternal nurturing instinct gets in the way of logic. I regularly read references to plants as babies on Internet houseplant forums and revulsion to pruning them.

This is a good article about the merits of pruning indoor container plants. It’s one of the best things you can do for your indoor plants. The author is a well-known garden writer. I don't often find accurate articles about plants in buildings written by outdoor gardeners, but this is one them.

Following is a particularly cogent excerpt from the article. Truth be known most of the so-called houseplant caretakers on web forums are outdoor gardeners who are only over-wintering their plants inside the house. Their gardening motivation is to grow plants as in “how big can I grow this plant.”

Maintenance of a decorative object would be a good goal for year round indoor plant owners. That’s what Reich says here.

Once the plant is back in its pot, the stems also will need some pruning to keep the top of the plant shapely and in proportion to the size of the container. The goal here is beauty, not growth. After all, you're not seeking maximum growth from a houseplant that already is full size -- full-size for your house, that is.

Flowers and Plants in the UK

Click the photo for Interesting statistics and other information from the Flowers & Plants Association (UK).

The UK Market

The UK fresh cut flower and indoor plant market is worth £2.2 billion ($4.1 billion US) at retail level. To put this in perspective, the UK music industry is worth around £2 billion ($3.7 billion US).

This represents an average spend per person per year of £36 ($67) - (£28 ($52) on flowers and £8 ($15) on plants).

While this is a good increase from the 1984 value of £8 ($15) per person, it still comes nowhere near the rest of Europe, where people regularly spend £60-£100 ($111-$186) per year on cut flowers and indoor plants.

In the UK we spend £9 ($17) on cut flowers for every £1 ($2) we spend on indoor plants. This may be because most people in the UK have gardens and so spend more on outdoor plants; or it may be because the British like to hang on to their houseplants when they are past their best, instead of treating them as a disposable item to be enjoyed and then discarded, like fresh flowers.

Around 60% of the £2.2 billion ($4.1 billion) spent represents people buying flowers and plants for themselves, for their own homes. Even five years ago, most people in the UK only bought flowers for special occasions like weddings and anniversaries, and may have bought a pot plant when visiting someone. Now, we all realise the beauty of having fresh flowers and plants around our homes, workplaces and public places. Why should they be saved for special occasions only?

How About Bunny Ears?

Click to enlarge. The Sansevieria on the right grows in a ceramic cookie jar. It would be cool for a little kid’s room. So why don’t we call these “Bunny Ears” instead of Snake Plant or Mother-in-law’s tongue.

It’s neat that Sansevieria has had a comeback of sorts. It’s a very versatile plant and there are a few more species now available at retail. There should be many more. Sansevieria trifasciata ‘Laurentii’ used to be the sole choice and it rather overstayed its welcome.

I split the middle and left plants from a 6” pot size plant in May 2005. It was a big box store plant from June 2004.

The plant on the left may look like it’s installed in a typical clay pot but it isn’t really. It’s a no-hole terracotta planter from IKEA. The plant is growing in expanded clay pebbles (hydroculture) inside a recycled yogurt container.

The middle plant presents an excellent learning experience. You can actually see the root system and water consumption. That’s a clear glass bowl from IKEA. There has been no algae growth because this succulent uses very little water. To control algae, I add hydrogen peroxide periodically to other plants growing in clear glass containers.

The cookie jar plant is growing in sub-irrigated soil based media. There is no need for drainage holes if you use either soil based or expanded clay pebble sub-irrigation (aka hydroculture) methods.

Although Sansevieria is a succulent, you will not need a special cactus and succulent soil mix either. The need for special soil mixes is a necessity only when you top water. People do all kinds of unusual things to compensate for the inherent faults of drench and drain watering.

Sub-irrigation (using either soil based or expanded clay pebble media) allows you to feed very small amounts (2 ounces for example) of water directly to the plant root system with pipette-like precision. It is impossible to do that with drench and drain watering.

If you’re skeptical, try it yourself. It isn’t rocket science.

Some Good Advice Here

USA Weekend published “24 sizzling tips to live it up” in conjunction with Prevention Magazine. There were many good tips I related to but none more than this one of course.

Keep plants in your home and office. Indoor plants have been linked to reductions in stress, fatigue and illness. And displaying them sparks social interaction.

Not having visited Prevention.com previously I did a site search to see what they’ve published about the overall subject of plants in buildings.

I’ll publish some interesting results in separate posts.

Plant Photo Set on Flickr

There are now 18 plant photos posted on Flickr.com. The set of thumbnails are here. You can view them as a slide show .

Ficus Surgery Required

This 6” pot size Ficus benjamina from a big box store was planted in a 7” diameter x 6” tall clear plastic food container on September 2, 1998. I decided to replant it into a microwave food cover and melamine bowl.

Click to enlarge. Number 17 is one of the original plants in the lab. After almost 8 years, it required a bit of root system surgery to get it to fit into the microwave food cover.

Click to enlarge. Although I don’t recommend that an inexperienced person do this, it didn’t’ really require highly specialized skills. What it does require is the confidence that this somewhat radical root pruning will not harm the plant.

Click to enlarge. The tree in the microwave food cover is now installed in a melamine bowl. A polyester AquaPad under the cover facilitates capillary action and sub-irrigation.

Ficus benjamina trees are far more durable then their reputation and this demonstrates it. I root pruned it yesterday and today there are no yellow leaves. The tree has not dropped a leaf.

The important factors are sufficient light and the right amount of water using sub-irrigation. I’ll post progress pictures at a later date.

Ficus in a Microwave Food Cover

Click to enlarge. This is a five-year-old Ficus Benjamina transferred into a microwave food cover planter. It started out as just an ordinary 6” pot size plant from a big box store.

Microwave Food Cover Planter

Click to enlarge.The three components shown here will make as good a sub-irrigation planter (inappropriately called “self-watering”) as there is on the market. The bowl is a 12” melamine bowl from Rite-Aid for $4. I have also purchased the exact same shape and size bowl from Ralphs supermarket. A Chinese import, I suspect they’re available in supermarkets and other retail stores around the country from time to time. Look out for them.

Clear plastic microwave food covers are widely available in discount stores and supermarkets from $2 to $4. Those with flat bottoms are easier to fit into shallow bowls. The AquaPad is polyester backing material cut a little larger than the diameter of the microwave food cover bottom. The material is widely available in fabric stores

The only fabrication required is cutting the polyester AquaPad to shape and drilling a series of holes (approx. 1/8”) around the bottom of the microwave cover. There are holes (slots) pre-formed in the cover but they’re too high to make contact with the AquaPad for capillary action to take place. They're probably good for aeration though. Who knows? For sure they don't hurt anything.

The microwave cover inner planter also fits several other melamine bowls I’ve found at retail. Several of them came from Party City.

Pour a measured amount of water in the bottom of the bowl. It will soak the AquaPad. In contact with the microwave food cover, the water will then rise by capillary action up through the bottom holes into the soil and root system.

You should never add so much water that it rises all the way to the soil surface. You don’t want fungus gnat larvae to find a home in moist surface soil and of course, you don’t want to overwater the plant. Incidently, you can now see the soil moisture level through the walls of the microwave cover. Save your finger and fingernails for better uses.

Unlike drench and drain top watering you can now control the soil moisture with pipette-like precision...and eliminate any exposure to fungus gnats.

It works beautifully. Here is a Schefflera arboricola installed the same way except in expanded clay pebble media (hydroculture). If, for some reason you’re stuck on the “poke, pour, and pray” method, I sincerely hope you get over it. If you do, your plants will love you for doing it.

Incidentally, I just happened to display an African Violet bowl here. Women have been sub-irrigating AV’s for decades only to avoid water damage to the satin-like leaves. There is nothing physiologically different about African Violets to make them any more suitable for sub-irrigation than any other plants.

Sub-irrigation works for all terrestrial plants including cacti and succulents. If you find this hard to believe, just make yourself a cacti and succulent bowl using this same method.

Keep the soil moisture drier simply by adding a smaller amount of water. Unlike drench and drain watering, you never soak the soil which is much more suitable for desert and dry climate plants. You'll be able to see the soil moisture level and status of the root system through the plastic microwave food cover.

Caveat Emptor

These so-called bonsai plants are widely distributed both on the web and in retail stores. For example, there are more of them here on Overstock.com.

In my professional opinion they are an egregious misrepresentation of both bonsai and what is described as an “easy to care for” indoor plant. They are neither.

Please do not buy them. They might make a good first impression as a gift but recipient disappointment will soon follow when the plant dies. That, of course, is not the lasting memory you want to leave with a business prospect, associate or personal friend.

Practiced for centuries in China and Japan, the art of bonsai captures nature's beauty in a confined space. Not your traditional bonsai tree, the exotic, tropical Sago palm brings a bit of paradise down to earth. Exclusively from RedEnvelope.

* easy to care for, our miniature version adapts to indirect light or full sun and needs only occasional watering
* arrives in a modern, white ceramic pot with an ornamental river rock
* plant measures 14" to 17" high
* pot measures 7" x 5 3/4" x 2 1/2" high

story card (delivered with the plant)
One of nature’s most easy-to-care-for plants, the exotic Sago Palm brings a bit of paradise down to earth. This miniature version is very slow growing, allowing your palm to remain in the same container indefinitely. One of the oldest plants on earth, it will produce only one set of leaves per year and will take several years to develop a “trunk” of much size.

To care for your palm, follow these simple instructions:
Place your palm indoors in an area that receives very bright sunlight. Once the danger of frost has passed, you may move your palm outdoors to a lightly shaded, sheltered area. Before frost, bring your palm back indoors. Water thoroughly when the top half-inch of soil feels dry. Do not keep the soil wet or soggy. During cooler months, watering may be reduced to allow the soil to become nearly dry. Remove any dry or brown leaves by cutting off the leaf stalk near the trunk.

USDA Reports for 2005

Read the U.S. Department of Agriculture Floriculture and Nursery Crops YEARBOOK – SUMMARY in text format or PDF format.

For those interested in the wholesale sales rank of various potted flowering plants:

Poinsettias 30%
Orchids 18%
Florist Chrysanthemums 9%
Spring Flowering Bulbs 6%
Florist Azaleas 5%
Easter Lilies 4%
Florist Roses 2%
African Violets 2%
Not identified 25%

Statistics for potted foliage plants by species are not provided.

Excerpt: Potted Flowering and Foliage Plants

Sales of flowering plants in pots climbed 1 percent in 2005 to almost $809 million. Potted foliage plants expanded 7 percent in sales to $652.1 million, but foliage hanging baskets dropped 10 percent in sales to $68.9 million. Potted flowering plant sales’ gains in 2005are attributed largely to orchids, which closed in on $144 million in sales, up from $129 million in 2004. Orchids are the fastest-growing potted flowering plant, more than tripling sales of $47 million a decade ago.While poinsettias remain the biggest seller at $242.3 million in 2005, sales are down 2 percent from 2004 and fell farther below their peak of $255.3 million in 2001. Imports of poinsettias, largely shipped from Canada, were more than $6 million in 2005, but are down from $10.4 million in 2002.

Potted orchids are the most expensive major potted flowering plant at $8 per pot on average (wholesale value) in 2005. Poinsettia prices are about half at $4.10 per pot (all sizes). Similarly priced potted flowering plants are Easter lilies at $4.24 and florist azaleas at $4.14 per pot in 2005. Prices of all major potted flowering plants averaged a record $3.66 per pot in 2005, up 2 percent from $3.60 in 2004. Again, California leads in sales of potted flowering plants with $199.3 million in 2005. Florida’s sales of $94.6 million amount to less than half of California’s. California grows the most poinsettias and orchids, but Florida is a fast-growing source of potted orchids.

Average sales per grower are highest for orchids at $663,447 in 2005. For all potted flowering plants, average sales were $384,660 per large grower, up 6.5 percent from $360,927 in 2004. Average sales of poinsettias were $160,467 per grower, up 3 percent from 2004, and the next highest after orchids. Similar sales per grower were recorded for florist chrysanthemums, which were up 7 percent from 2004. Nevertheless, average sales per grower for potted foliage plants were $706,507 in 2005, up sharply by 13 percent. All these sales are record amounts, attesting to the strong domestic market for potted flowering and foliage plants. Although competition from imports is rising for orchids and other flowering plants, the share of imports in consumption remains at a low 3 percent compared with cut flowers’ 66 percent.

Potted foliage plants for indoor or patio use have the third largest sales among floriculture crops at $721 million, coming after bedding annuals and potted flowering plants. Nearly 70 percent of sales of U.S. foliage plants are earned by Florida growers, with California earning a distant 15 percent. Most foliage plants are marketed in metropolitan areas and face minimal competition from imports except fake plastic plants.

Easy Care Flowerless Indoor Plants

Click to enlarge. These indoor plants may not flower, but most anyone using modern digital age methods can keep them alive and healthy looking.

It’s no secret that women like flowering “houseplants.” That’s fine, but their degree of difficulty is in the range of 8-10 on a scale of 10. Plants need much more light to flower than they do to maintain foliage. Other than African Violets there are very view easy-to-care -for flowering indoor plants.

Note that the majority of the so-called “houseplants” in the What is a Houseplant? post are flowering plants. In my opinion, this is a disingenuous pitch to female buyers. Very few indoor plant maintainers will have the skill and necessary interior environment to keep any of these plants alive, no less flowering.

Even commercial plant maintainers refer to flowering plants as “color rotation.” All those flowering bromeliads, chrysanthemums, kalanchoes and poinsettias you see in hotel lobbies and malls are replaced every two to three weeks.

My best advice is to spend your money on cut flowers. In the end, you’ll save money and remove the frustration of killing “houseplants” that don’t stand a chance of staying alive for other than a limited time.

Happy Fourth of July!

What is a Houseplant?

The botanical answer often given to this question is that there is no such thing as a “houseplant.” Well of course there is for those of us who like some contact with the natural world inside our homes. However, what are the specifications or parameters that define just what a “houseplant” is?

The question came to mind recently when someone posted a request for online houseplant sources on a popular houseplant forum.

Someone replied with this link. There are about 120 “houseplants” included here in this section of the online catalog. As an interior plantscaping professional, I would say there are only about a half dozen of them that are widely recognized as good indoor plants.

Unfortunately, there are self-styled green thumbs camped out on these forums who recommend all kinds of plants that are unsuitable for building interiors. What they fail to reveal is that their plants live a good part of the time outdoors over the summer. They also neglect to disclose how many of them they kill.

The overwhelming majority of these plants are high light requirement plants suitable for outdoor gardening only. I’m not just picking on one supplier. There are sellers all over the web who market plants that are inappropriate for indoor growing. There’s no law against it…although maybe there should be.

Perhaps the best site on the web that defines plants suitable for use inside buildings is Plants-in-Buildings.com. I’ve recommended it before. In my opinion, it is clearly the best website on the subject. It has excellent, well-written content and it's worth spending significant time surfing through the site. Check out the Specifier's Guide - Plant Selector.

It took a while to do, but I searched for all of the so-called “houseplants” and found only eight out of over 120 listed. The Tibouchina urvilleana in the photo above was not one of them. Again,…caveat emptor!