African mask (Alocasia x amazonica)

Some people call it African mask. It could be the most arresting of all indoor plants. If you planted it outdoors during the summer, it would be a stunning plant in your shade garden, although you would have to bring it inside around this time of year. Its leaves die back when temperatures dip into the 40s, but they often reappear, thanks to tuberous rhizomes, the following summer.
The plant in question is Alocasia x amazonica, a hybrid species that clearly looks like one. Emerald black foliage is highlighted with thick, white venation. Leaf texture is of a leathery plastic consistency.
Because of African mask’s exotic look, it is often overpampered, which means overwatered. African mask, like most of its aroid kin, appreciates soil dryness between waterings and should only be watered when soil is dry at a 2-inch depth.
Still, even grown indoors, its leaves will die back from time to time. When this happens, do nothing except for keeping the soil barely moist. There’s a good chance you will see a new batch of leaves sprout from the rhizome and open up when summer comes.
Aroids are popular indoor plants. Among them are devil’s ivy, the most common desk plant on the planet. Anyone who has worked in an office has surely encountered it.
Devil’s ivy (Epipremnum aureum) is also known as pothos, and is typically encountered in its gold and green variegated form, but the silver and green version is quite popular, too. Foliage is heart-shaped and equally happy whether growing horizontally along the back edge of your desk or clambering vertically up the side of your cubicle.
Elephant ears are African mask cousins. Elephant ears (Calocasia spp.) are grown ornamentally and their leaves may reach several feet in size. Green and black elephant ears are available.
The elephant ears that you see growing in shade and water gardens throughout the Los Angeles area is known in the tropics as dasheen or taro (Calocasia esculenta). Just as wheat is the staff of life in temperate zones, taro is the staff of life in many tropical regions.
Taro’s edible, tuberous corms are toxic, containing calcium oxalate. This is advantageous to the plant since it keeps animals from consuming its corms, yet cooking or simply soaking the corms in cold water overnight weakens the toxin. The starchy sweet and nuttily flavored corms may then be baked, boiled or roasted for consumption.
In the Los Angeles area, you can also grow taro as a food crop. There is a large plot of it under cultivation at Sepulveda Gardens in Encino.
Pomegranates, avocados and plums
Q I have a large tree with many pomegranates on it but they are all splitting open. What is the cause of this? Last year they didn’t do this.
—Sharon Bianconi, Antelope Valley
A Fruit splits as a result of uneven water application. Whether we are talking about pomegranates, oranges or tomatoes, the fruit-splitting phenomenon can nearly always be explained by a sudden influx of water after a period of dryness.
Cells in the fruit expand more rapidly than cells in the skin or rind, resulting in splits. Mulching, or application of a 2- to 3-inch layer of organic material such as compost, aged wood chips or straw on the soil surface, is a good way of evening out the moisture supply to roots.
There are also certain pomegranate cultivars, such as ‘Francis,’ that are less likely to split than others. Your semidesert location makes it more of a challenge to grow pomegranates without splits, since blistering-hot temperatures demand sudden water uptake that causes splits. Split fruit, incidentally, is an advantage as far as the pomegranate is concerned, since splits make it easier for seed-dispersing birds to access pomegranate seeds.
Q I planted a Little Cado tree about 4 years ago and this year it produced seven avocados. I put one in a paper bag for about seven days. It felt soft so I proceeded to cut it in half only to find it was hard in the center. How do you tell when they are ripe?
— Barbara Wi, Artesia
A Little Cado is a dwarf avocado cultivar recommended for patio containers since it reaches a height of only 8-10 feet. It is also a self-fertile tree.
Most avocado trees, while they may produce a small crop on their own, will never produce anywhere near their potential unless there is a different cultivar in the vicinity.
Little Cado, which bears green, smooth-skinned fruit, does not require a companion cultivar to prosper. Internet research reveals a widespread method for testing an avocado fruit for ripeness. It’s all about the stem. If you try to pull off an avocado stem and the stem resists, the fruit is unripe. If the stem comes off, examine the color underneath, at its point of attachment. If the color there is brown, the fruit is overripe. If that spot is green, the avocado is ripe and ready to eat.
Q I have a ‘Krauters Vesuvius’ flowering plum in my front yard. I planted it about 10 years ago (about 10 feet tall then). It is now 20 feet tall, but the last three years or so, it has leafed out less and less.
I read in your column about the short life expectancy of these trees. Am I now out of luck now with this tree? So disappointing. It was a nice color point against my eugenia hedge.
Please comment again on the longevity of ornamental plums. Any suggestions on any other purple leaf tree?
— Stephanie Vigneault, Glendora
A You are probably out of luck with this tree and, yes, like most other flowering plums, it is very short-lived.
‘Forest Pansy’ (Cercis canadensis ‘Forest Pansy’) is a gorgeous purple-leafed tree but, alas, it too seems to be short-lived in Southern California.
You might want to consider planting a smoke tree (Cotinus coggygria ‘Royal Purple’). It is a shrubby sort of tree that is planted for strictly ornamental purposes. I have seen it at a height of 12 feet and still growing.
There is also a purple-leafed mimosa (Alibizia julibrissin ‘Summer Chocolate’) that is not wide- ly planted but should be.
Standard mimosas (or silk trees) live for 25 to 30 years. There are many varieties of Japanese maple (Acer palmatum) with burgundy leaves but they are somewhat challenging to grow, requiring excellent light and acidic soil, and they will show burned leaves from either heat scorch or low humidity. Some people even water them with distilled water since the alkaline minerals in our water supply can also cause leaf burn on Japanese maples.
There is one other possibility. European copper beech (Fagus sylvatica ‘Atropurpurea’) has bronzish-purplish foliage, a naturally symmetrical form and requires little, if any, pruning. It is more of an East Coast than a West Coast tree, but I have seen it growing in your area. Mature height in our part of the world is 40 to 50 feet and it grows around 1 foot per year.