The white and yellow variegation of the bromeliads has been selected by horticulturalists as a desirable trait which they consider adds to the visual beauty of the plant. but the subsequent reduction of chlorophyll reduces a plant's vigour and makes it just that bit slower to grow and needs more exacting conditions and attention. Especially in Neoregelias, the pigments within the foliage of bromeliads known as carotenoids which vary from yellow through red to orange become more vibrant when displayed on a white background - that is the white variegated portion of the leaf. This kaleidoscope of color is probably why variegated bromeliads are so popular and why growers totally disregard the reduction of vigor.
The term marginata refers to a leaf with a stripe up each side of the leaf. Variegata is the term used for plants with a stripe down the centre of the leaf. Striata is a multitude of stripes and lineatum, a multitude of fine stripes. This is a simplified version.
The actual proportion of white or yellow to green is a personal thing but for marginata I prefer about 20% of white on each side of the leaf - a total of 40%, for variegata 30% and striata and lineatum 50%. In a lot of occasions the definition of marginata and variegata in some of the plants need a little imagination and is more a goal to obtain than actuality.
The grower has to juggle a number of factors.
1. If the plant does not develop too much white you shouldn't have many problems. That is why I try to keep the variegation to the percentages previously mentioned.
2. Selecting pups that will produce a plant with balanced markings. The same percentage of white on each leaf.
3. If the humidity level drops too low you will find that cells in the variegated portion will have a tendency to collapse and then spread to a larger section of the leaf but will generally be confined by the green section. Where the percentage of green is very small it will not confine this collapse and will spread to the whole leaf. A green edge to the leaf has the ability to protect the white section from extreme conditions. In the spiny bromeliads when the edge of the leaf is white, the spines are still dark. In all Neoregelias and Aechmeas except some spines on Aechmea 'Lucky Strike'. Now if you think that's interesting, when you check out Ananas you will find that all spines are white. A rather interesting experiment is with Cryptanthus 'It'. This plant will sometimes throw albino pups. You can maintain these plants in perfect condition indefinitely with a combination of glasshouse and automatic misting system. Removed from these conditions and within 24 hours the plant will start to collapse. Whether it's only Cryptanthus that can be maintained under these conditions, I don't know but I suspect it is so. I have used Cryptanthus 'It' as an aquarium plant and they lasted for a number of weeks in perfect condition excluding the bits the fish ate! Unfortunately some fish find red an aggressive color and they beat up on the Cryptanthus!.
4. The definition of stability is probably what percentage of perfect variegated pups you are receiving from your plant that makes you happy. Some plants never seem to be stable but sooner or later you may obtain through your production, a plant that is more stable than you have previously noted. The trick is to recognize such a plant and be able to take advantage of it.
The rest of this article will deal with individual plants and their idiosyncracies.
Ananas comosus marginata. Pineapple plants in South East Queensland will stress out during our winters unless they have sufficient nutrient. All the variegated forms of Ananas comosus and Ananas 'Cayenne' types need to be kept on a good balanced fertilizer program or they will mark. The tips dry out and die back and the plant starts to yellow. Very good light during winter is a must or the plants go back.
Ananas bracteatus var. tricolor (marginate). This plant is slightly more winter resistant than Ananas comosus or Ananas 'Cayenne'. Side by side they will mark before Ananas bracteatus. This plant will also respond better under a fertilizer program and good light during winter.
Bromelia serra variegata (marginata). It seems this plant has been misnamed all over the world. You may have it in your collection under the incorrect name Bromelia pinguin variegata. The plant responds well to a fertilizer program but, as the pups are on long stolons, I prefer to grow the plant in a 14" tub which allows the stolons to wind around inside the pot on the soil surface and this will help the pup to throw roots before it is removed.
Aechmea comata var. makoyana. The joy of growing this plant is to have a semi-mature plant with it's golden yellow variegation when it throws pups and they are in bright light. The pups will be lacquer red. It looks great.
Aechmea 'Ensign' (marginata). A cultivar of Aechmea orlandiana. I would recommend a consistent fertilizer program, very good light and plenty of air movement, water and good drainage. This plant requires attention or perfect conditions to flourish. The variegation is pure white and has a tendency to mark. To counteract this, maintain a reasonable humidity level. I consider a lack of humidity in our winters more of a problem than cold.
Aechmea fasciata (marginate and variegata). Dividing all the forms of this plant into two groups you will have plants that maintain the variegation on all leaves for the full life of the plant. The other group have a variegation that fades out on the older leaves back into green. I would have a tendency to drop this style in preference to the stable group.
Aechmea 'Foster's Favorite Favorite' (variegata). A cultivar of Aechmea 'Foster's Favorite'. To do well with this plant it needs to be grown in the shade and slowly.
Aechmea 'Kiwi' (variegata). A cultivar of Aechmea fasciata. This plant has a series of red lines up the center of the leaf. It's well worth having in your collection.
Aechmea 'Mary Hyde' (marginata). A cultivar of Aechmea nudicaulis. Wide stubby leaves and a good clumping plant.
Aechmea 'Mend' (marginata). Cultivar of Aechmea lueddemanniana also Aechmea lueddemanniana 'Alverez' (variegata), Aechmea lueddemanniana 'Quadricolor' (variegata) are derived from this species. Aechmea 'Pinkie' (striata) is a seedling of Aechmea 'Mend'. You will find the seed of Aechlnea 'Mend' will produce a large percentage of variegated seedlings. All cultivars require adequate fertilizer or they languish in their pots.
Aechmea 'Nationalis' (marginata). Cultivar of Aechmea ornata is a stunning formal plant but reluctant to flower. Has no problems except the tip of each leaf. There is a variegate form but is not as stunning as 'Nationalis' but is still interesting.
Aechmea nudicaulis var. flavomarginata. An extremely good plant. Does not seem to mark and has good strong leaves with a rich gold color. A good clumping plant.
Aechmea 'Samurai' (variegata), Aechmea 'Shogun' (marginata). Require a fertilizer program to multiply and requires adequate drainage, air movement and water. They are a cultivar of Aechmea chantinii and require the same conditions.
Billbergia 'Kyoto' (marginata). A cultivar of Billbergia pyramidalis. This plant needs to be kept growing with a moderate fertiliser program to do well.
Cryptanthus bromelioides var. tricolor (Now known as 'Rainbow Star'). The first requirement for this plant is humidity. If you do not keep it up to the plant, it will mark badly. It likes bright light but should it result in a decrease in relative humidity, drop the light back. A moderate fertilizer program is necessary. Be selective with what plants you propagate.
Cryptanthus 'It'. Like all Cryptanthus, humidity is important. But if you feel the leaf, you will find it has a central thickened rib. Cold drips on this rib during winter will cause the cells to collapse, badly marking the center rib.
Guzmania 'Superba' or Guzmania 'Broadview'. To do well with these plants, it is necessary to have a constant fertilizer program. They are a joy to grow.
Guzmania zahnii variegata. This plant is slow growing and must be continually fed. If you find that the plant is a tuft of leaves on a long spindly stem, you may find the stem has withered and when spring comes along, behead the plant and start again.
Tillandsia viridiflora (variegata). I acquired an adventitious pup of this plant. It was plain green and they assured me it would end up variegated. About three years later I am a believer. It is growing into a very nice plant. I have been assured this is typical of the plant.
Vriesea 'Milky Way' (variegata). This plant is a cultivar of Vriesea glutinosa and retains the characteristic habit of the species in that it will produce adventitious pups and if you are prepared to put a bit of an effort into it, you will average about 8% variegated.
Vriesea saundersii x platynema (marginata).(now 'RoRo') The trick is to select your plants to eventually provide margins representing 20% of the leaf surface. You will grow a magic plant. It does not mark very easily. A characteristic of this plant is that the pups come away and they appear as if they are green. If you get out your magnifying glass, you will find a hair line of variegation on the margin of the leaf. With each new leaf the variegation will improve and you will wind up with an attractive plant. The real winners are the pups with obvious variegation. These have the ability to develop into real show plants. If you can select the pups of this plant to give you a stripe representing 30 to 40% of the leaf, you will wind up with a real show plant. Bright light develops an orange pink hue to the variegation.