Garden Blog - Top Tropicals

Hardy avocados

Q: I intend to gift three avocados, at least one type A and one type B, to a friend who lives in an area where the temperature never goes below 25F. The idea is to give them a ripening season as long as possible. Which combinations do you suggest, and which are the A and B?

A: When talking about "A" type and "B" type in Avocados, it is referring to the flowers. An avocado will produce both male and female flowers on the same plant. "A" type means that the flowers are female in the morning and male at afternoon. "B" type means that the flowers are male in the morning and female in the afternoon. If you plant to start a commercial growth, then it's important to create a proper mix of both types. However, in hot and humid climate a single tree produces flowers of both types, so it is not necessary to have both A- and B- types planted together in backyard. Even a single tree produces enough fruits for home gardener.

It is also important to know that while there are more cold hardy avocados, it refers to a full grown established tree. They will still need protection from the cold until they are bigger and more established. One can not expect a small tree, which was planted in June, to survive the first winter. It'll take few years until the tree is "harden" enough.

Wurtz Avocado: Fruits from May to Sept. Dwarf hybrid. It is very compact and slow growing, reaching only about 8-12 feet at maturity. Distinctive weeping growth habit. Suited for planters, containers, patios, greenhouse use. Great for dooryard or container growing. The tree can handle temperatures to 25(F) degrees. Production is good and it is a consistent bearer.

Day Avocado: Fruits July to Sept. Day avocado is green, smooth skin and is shaped like a club. The fruit is of very good quality and has a nice buttery consistency. The slender tree is relatively cold tolerant and produces July through September.

Fuerte Avocado: Fruits Nov to June. Relatively cold hardy variety. Green fruit, elongated,flavor excellent, buttery. Vigorous compact tree with decidedly alternate year bearing habit. Ripens November to June.

These three will provide you with fruit ripening during the whole warm season. For the most cold hardy avocado varieties, see this info sheet.

Growing Mexican Flame Vine as an annual

Q: While down in Fort Myers a few years ago, I saw this plant - Senecio confusus or Mexican Flame Vine, growing over chain-link fencing. At any rate, I fell in love with the plant then and there, only to later see it up here in Wisconsin, albeit down in Madison at The Centennial House, a noted botanical garden. This has led me to believe it may be possible to use this plant up here in the north as an annual. I could really use the orange coloration in mixed containers, etc. What I would like to try to find out is, will it grow and flower sufficiently within one of our growing seasons up here to make the choice worthwhile? Again, seeing it at Centennial House at least leads me to believe it may be possible. China where the flower was admired for its beauty and believed to have medicinal properties that promoted good health and long life. The Japanese Emperor was so smitten with the kiku flower that he adopted it as his personal crest, and it remains the insignia of the imperial family today. The art of growing and displaying Kiku for the Emperor's garden represented by amazing Imperial styles: Ozukuri, Ogiku, Kengai... Imagine growing out of one stem a single chrysanthemum trained to produce hundreds of simultaneous blossoms in a massive, dome-shaped array.

A: Mexican Flame vine is a good candidate to be grown as annual, thanks to these features:
- extremely fast growing
- it flowers in small size and young age
- long flowering period (2-3 months depending on conditions), throughout early Spring into Summer, sometimes it has a second blooming season by end of Summer.
- we keep large mature plants in stock year round, so you can have blooming size specimen as early as spring once your temperatures reach 65F so the plant will feel comfortable and develop quickly.
- easy to propagate - more plants can be made for next year season.

In winter, a potted plant can be cut back and kept in semi-dormant state indoors - garage, enclosed patio, with temperatures around 50F and above. Some gardeners from North prefer to plant a tropical specimen with a pot into the ground (make sure to add extra drainage holes), and when winter comes, it makes it easier to dig it out and save till warm season.

Growing mango in hot Arizona

By Mike D, Mesa, AZ. Despite to what you may think, mango can be successfully grown in desert Arizona climate. It has good heat and drought tolerance. It's possible providing the following:
1) Winter protection of a young plant when temperature goes around or below freezing. Try to plant trees in locations where they're protected from cold wind. Minimal temperatures vary widely. Areas which are closer to downtown are few degrees warmer, while outskirts can be very cold.
2) Some people are lucky enough to live in areas with good soil. However, most of us will have a so-called hardpan (extremely compacted desert) or caliche (layers of soil cemented together by calcium carbonate). Check with your local county extension office to determine how to deal with such conditions. Gypsum is usually used to loosen compacted soil.
3) When planting, dig a large hole making sure it has good drainage. Plant tree as usual, add mulch around it. It helps to conserve moisture.
4) Best time to plant is late Fall or early Spring, so mango can get established before Summer heat.
5) Plant where tree gets few hours of sun.
5) Water a lot until established. Once established, water when soil is dry.
6) Small plant may need protection from summer heat. Use shade cloth.
7) Mango requires very little nitrogen fertilizer. In hot climate, overdosing nitrogen may result in quick plant decline. Use balanced low nitrogen slow release fertilizer or avoid nitrogen completely. If you use mulch, then decomposing mulch provides enough nitrogen. Foliar spray of micronutrient solution is recommended during active growing period. Read more...

Growing gardenias indoors

From Brian B, WI: Just wanted to share this photo of one of the plants my parents got from you 3 months ago.

Q: Gardenia taitensis is my favorite gardenia. I would need to keep it indoors under a grow light. Is it worth trying to grow indoors or is really difficult? If so, can you recommend and indoor plant that has big fragrance and blooms often?

A: When growing gardenias indoors, four most important factors must be taken in consideration:
1. Bright light (Southern window and/or proper lighting set up)
2. Proper watering (gardenias love water, but roots are very sensitive to excessive water)
3. Rich organic soil with perfect drainage characteristics, regular feeding with high phosphate component and micro-elements containing Iron or Ferovit.
4. Insect control (inspect underneath leaves regularly and apply systemic or on-contact treatments as needed). See Top Tropicals video on easy insect control.

We definitely recommend Gardenia taitensis (both single and double flower varieties) for indoor culture. Another species, Gardenia vietnamensis, is even easier in cultivation as it takes wide range of conditions and may tolerate slight overwatering (unlike other varieties which are more sensitive). These three mentioned gardenias are somewhat tolerant to low light conditions. Under a proper care, they will grow successfully even in bright shade, however for blooming they require as much light as you can provide. Properly adjusted growing light may be helpful. You may refer to our article about indoor plant lighting in our magazine Tropical Treasures, Issue # 15, or website page.