Monday, March 19, 2012


Fig. 1      Abutilon x hybridum - solitary and pendent flower. (February 15, 2012)


New Plant for My Garden
Last fall, I bought a foot-tall blooming Abutilon plant from the Farmer's Market in Placerville. Winter is almost over and the same plant remains blooming and seemingly unrelenting (Fig.1). The plant has flower buds that come out wrapped in a blackish red calyx (Fig. 2) which eventually opens into a bell-shaped pendent flower with overlapping dark scarlet petals and even a red peduncle (Fig. 1).
Twelve years ago when there were no tall trees in my backyard, I planted my first Abutilon and I was very pleased with its vigor. Sadly, on its third year, it began to shade some important plants round it. It had to go in favor of the other ones. But because of its desirable characteristics as a plant, I bought this new plant (Fig.1) as a replacement for the old one.

Fig. 2     Unopened Abutilon flower

About Abutilon
Common names include: Flowering maple; Parlor maple; Indian mallow; Chinese lantern, etc.  They are closely related to Hibiscus (Malvaceae family).  They are occasionally referred to as "maple" because of the resemblance to the actual maple trees in the shape of the leaves being palmate.  

Abutilons are evergreen small trees that can grow up to about eight feet tall. They are fast growing  plants. Given the right conditions they can reach their potential height on the second year.   They bloom almost year round in our area. Of the numerous varieties, the most popular ones bear solitary and pendent flowers like the one I have now (Fig. 1 and Fig.2). There are some that bear flowers in panicles - dangling like their solitary counterparts.   Green Acres, the mega nursery in the area, currently offers a wide selection of Abutilon.

Tips in Growing Abutilon

1.  Microclimate.   Abutilons like places with a lot of light up a point when temperature interferes with its growth.  In hot and dry areas like here near the Sacramento area, the plant prefers to grow in a sheltered south-facing location.  Afternoon shade helps reduce excessive transpiration and scorching of the flowers.  On the other hand, in places with cooler temperatures and more rains, full sun would work well.  Always remember to garden with microclimate instead of the generic recommendations for your plants.

2. Fertilization.  Being fast-growing and ever-blooming,  the plant benefits from adequate fertilization.  Phosphorous fertilization during the first and second year of growth ensures a strong root system.  If it is grown in a container then regular application of a slow release balanced fertilizer is more important than those planted in the ground.  The plant is responsive to fetilization as much as it is expressive of nutritional deficiency.  Chlorosis is the first sign of nitrogen deficiency but make sure that it is not caused by insufficient or excessive watering.  In general, I withhold fertilization starting in late fall to allow my evergreen plants to rest a little. 

3.  Pruning.  The plant may be pruned to regulate its shape and size. In the spring it is best to prune the tree, removing all branches that have died during the previous season, before the temperatures warm up.  Pruning may be done anytime to remove branches that stick out of place and also to encourage branching for a fuller shrub. 
Abutilon: evergreen and ever-blooming perennial for the protected sunny location in the garden.

Saturday, March 17, 2012


Fig. 1    Trifolium repens 'Atropurpureum'

Trifolium repens L. 'Atropurpureum' (Fig.1) is one of many varieties of the plant that is commonly known as clover.  It is a spreading perennial plant primarily grown for its purple foliage that floats above the long spindly petioles.  This plant is supposedly valuable as a ground cover for hot and dry areas making it a good choice for erosion control. 

This plant (Fig. 1) was available at our local nursery last week and I decided to try it in my garden.  Initially, it will be planted in a container for observation to determine its growth vigor before releasing it to the ground.  One can never be too cautious about plant families that have a reputation of being weeds.  

The dark purple leaves (Fig. 2) provided the reason for this variety to be called Atropurpureum.  I am curious to see whether the color will change under higher light intensity in the summer.    

Fig. 2    Trifolium repens 'Atropurporeum'

This is as close as I can get to presenting you all a sprig of shamrock for luck...
Happy Saint Patrick's Day!

Thursday, March 15, 2012

Sweet Potato

 Fig.1     New sweet potato (Ipomea batatas) plant.

Nostalgic Introduction
If anyone would make a movie about my childhood days in the Philippines, sweet potato (Ipomea batatas) would show up over and over again in the background.  Sweet potato is a must-have crop. The roots are eaten as source of carbohydrates prepared as dessert or snack food.  Although it is nutritious and readily available, it does not have the reputation as a staple food unlike rice (Oryza sativa), corn (Zea mays) and cassava (Manihot esculenta).  As a root crop it has a low acceptance possibly due to its flatulent characteristic.   The young leaves, however, have a better reputation as green vegetable.  They are cooked in stews or prepared as wilted salad.  When wilted (not over-cooked) they taste like spinach.  Believe it or not, some varieties taste better than others.   The vines and the older leaves are used as feeds. 

Growing sweet potato is very easy.  In fact the American expression "Piece of cake", can be translated in Ilocano (my native dialect) as "Kasla agmula ti kamote" meaning "It's like planting sweet potato". There was a time when the roadsides in my barrio (village) were all planted with sweet potatoes.  They were beautiful.  Here on the temperate side of the globe, there is also an increasing popularity of the Ipomea (sweet potato) as an ornamental plant mainly for its foliage.

Fig. 2   Sprouts arising from stored sweet potato roots. (January 31, 2012)

Fig. 3 A clean cut on one side of sweet potato.

Regenerating Storage Organs
Now in my house, away from the barrio where I grew up, sweet potato only shows up on Thanksgiving and Christmas.  A month ago while cleaning my pantry, I was in luck!  I found two large sweet potatoes that were sprouting.  The immediate thought that came to mind was planting material.  They have been sitting there for at least two months.  Sweet potatoes, commonly known in the US as yams, are storage organs where food and moisture abound. Because of that, the cells within the root are kept alive and capable of regeneration - starting a new plant.  This is true for most of the food we eat that come in various forms of storage organs such as bulbs (onions - Allium cepa and garlic - Allium sativum); rhizome (ginger- Zingiber officinale); tubers (potatoes - Solanum tuberosum); and corm (taro - Colocasia esculenta).  All of these examples will regenerate when the right conditions are met.  In the home, the pantry seems favorable enough to initiate new growths on such vegetables.

Fig. 4 Wet paper towel encourages root growth on a sprouting sweet potato.

Conditioning the New Sprouts.
Plants grown in the dark, such as those shown on Fig. 2 are etiolated and lanky. This, however, can be improved by exposing them to diffused light.  What I did was cut one side of the root (Fig. 3) to provide a flat surface that would rest on the wet paper towel on a dish (Fig. 4).  It has been my experience that growth of adventitious roots is enhanced by moisture - so the paper towel was kept wet at all times. 

Fig. 5     One week of exposure to light resulted in healthy-looking sprouts.

Garden-worthy Plantlets.
After eight days of exposure to light, the sprouts showed a significant change in coloration (Fig. 5 and Fig. 2).   The young sprouts begin to produce chlorophyll giving the leaves a green color.  They have grown to be more stocky and strong.  The same principle applies to potato (Solanum tuberosum) seed tubers. When their sprouts are pale, give them some time to get exposed to diffused light before planting them.

The roots  (Fig.5) look like they are ready to meet the soil but I will have to keep them inside for a little bit longer until the temperatures get warm. 

The Role of Sweet Potato in Another Country
I invite you to watch this video to see how sweet potato is being used to end hunger in Mozambique.

Tuesday, March 13, 2012

HortiCOOLture: Enormous Aloe

Fig. 1   Aloe arborescens  (February 18, 2012 Pacific Grove, California)

A. arborescens, also known as A. perfoliata var. arborescens is commonly named as Octopus plant, Candelabra aloe, or Torch plant.  The plant is multi-branched with rosettes of tentacle-like, partly concave leaves, thus the name octopus.  Like most succulents, A. arborescens blooms once a year (spring to summer).  Each rosette then sends out a terminal upright raceme that is covered with red flowers - transforming the plant to resemble the appearance of a chandelier (Fig. 1). 

According to the AHS, this plant is a native of Malawi, Mozambique, Zimbabwe, and South Africa.  Based on the size of this plant (Fig. 1), however, the California coast seems to provide favorable conditions for its growth.  

This enormous Aloe arborescens is stunning but I will not have it in my yard because its leaves are sharply-serrated. 

Thursday, March 8, 2012

Boxwood: Regulating Canopy Density

Fig. 1   Boxwood (Boxus microphylla japonica 'Green Beauty') hedge.

Boxwood is a popular hedge material because it is evergreen with a dense growth  habit.   In my garden hedges of boxwood (Boxus microphylla japonica 'Green Beauty') provide walls around the lawn and divide the yard into different garden rooms.  When other plants die back in the winter, the boxwood hedges remain as strict reminders of the discipline that I have set for my yard. 

When leaves cease to be useful
Healthy leaves of boxwood remain on the plant for two to three years.  I have observed that the leaves that were cut during trimming in the spring of last year are still green and intact (Fig. 2).  Regular trimming maintains the shape of the hedges as it also promotes more branching.  However, as the new growths spread out, the older leaves get covered and deprived of sunlight.  Leaves that do not get enough sunlight become photosynthetically inactive and dependent creating an increased deficit on food supply for the ever increasing foliage.  Eventually, the dependent leaves get less and less ration until the plant decides that they are no longer useful for the plant.  Plants in general, have a very accurate accounting process in this regard.  When a leaf if considered unproductive, the plant will separate it by blocking the passage way for food supply until the leaf is completely dead and detached.  Technically, this process is called abscission.

Fig. 2  Boxwood retains its leaves for more than two years.

When less is more
To maintain a healthy boxwood shrub or hedge, the ratio of the active to inactive leaves need to be increased.  As a general rule, all leaves need to get exposed to sunlight. This can be achieved by thinning the branches to allow sunlight to reach into the depths of the canopy.  Thinning also improves air circulation within the hedge thus preventing the growth of diseases. 

Tips for Thinning Boxwood
1.   Cut off branches from within.  From the dense sides of the hedge, cut into the canopy, six to eight inches long - one branch at a time.  Repeat the process throughout until the desired density is achieved.
2.  Make way for light and air within.  The process creates open spaces or holes for sunlight and air to penetrate the interior canopy of the plant.  With time, new branches will grow from the inner canopy making the plants healthier and less likely to be infected by fungal diseases.

3.  Change canopy density.  While thinning, keep in mind to maintain the shape of the plant.  Thinning is not intended to change the size or shape of the plant.  Instead, it is the removal of excess branches from a crowded canopy. 

4.  Thin prior to the next growth spurt.  Boxwood put on new growth in the spring and fall.  When the need for thinning arises, it is best to do it before the next growth spurt.  It is easier to spot overlapping branches before the older branches get overgrown by the new ones. 

In my garden, some parts of my hedges are in need of thinning.  One of these days, with my sharp pruners, I will have a date with my boxwood.

It takes years to grow a good hedge of boxwood.  Thinning contributes greatly in keeping them healthy and strong.

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