January 2023

This is a fun time of year – sort of. Although cold and (normally) snowy outside, plant people are filled with joy and anticipation for the upcoming spring season. While ordering seeds can give us hope, we tend to like to get our hands dirty – literally. I find that this is a great time to propagate African violets. Yes, these plants can be somewhat challenging to keep long term; they are rather easy to propagate. I find that when propagating them, I tend to watch the adult plants more carefully and, therefore, they do better and last longer.

African violet in bloom. Photo by dmp2009.

Keeping African violets is rather easy if you follow a few simple ‘rules’. First, their potting medium needs to be fast draining. They will rot if the soil remains soggy for too long. This is best accomplished by either buying a potting medium designed for them, or simply adding some extra perlite to a regular houseplant mix. I have found that filling the saucer under the pot with water is the best way to hydrate the plants. Any water remaining after an hour or two can be discarded. Care should be taken to avoid getting water onto the leaves as this cause diseases.  This is another benefit of bottom watering as water is never being dumped on the leaves.

A regular, dilute (quarter strength) application of fertilizer with every watering works best for African violets, as opposed to periodic strong doses. These plants need bright light but will burn in direct sun. I have found them to thoroughly enjoy living under a table lamp. Although some specimens seem to hang on forever, to ensure a long-lived violet, they will generally need to be repotted once a year. This does not actually mean moving them to a larger pot, but just take them out of the pot and remove as much potting media as possible and replace it with fresh medium. Try and avoid too much damage to the roots, as this will hurt the plant. This freshens the rooting media by adding new nutrients, lessening media compaction and gets rid of any salts that may have accumulated on the media surface (a consequence of bottom watering).

If your house gets extremely dry during the winter, a pebble tray filled with water beneath the plant will help, as African violets like humidity. The air should move around the plant, as stagnant air leads to fungal infections that may result in death of the plant. Many people who collect African violets will use fans to move air across their growing tables in order to prevent fungal diseases.

Now that we have talked about how to keep violets, we can talk about how to propagate them.  This is my favorite part of working with these plants. I propagate a lot of different types of plants, but for some reason this is one of my favorite species to reproduce. The first thing you need is a very healthy and well hydrated parent plant. If the parent plant is not looking good due to lack of water, or has been growing in waterlogged soil recently, the propagation usually fails.  You will need a mature leaf from a healthy, adult plant. It should be free from any kind of injury, as this will be a pathway for disease organisms. By simply moving the leaf sideways, it should snap off the adult plant. I like to use a new, clean razor blade to trim the end of the leaf. The pros may use a hobby knife for the increased control and accuracy. Make a nice clean cut. Sometimes it is necessary to retrim the bottom of the leaf stalk after removing it from the plant. Next, dip the end that you just cut into some rooting hormone. The easiest to use, in my opinion, are the powder types, although there are some liquid formulations. The rooting hormone generally has some antifungal properties that help protect your plant during this process. Once this is done, you are ready to pot.

A young African Violet, propagated by the author, that is ready to be potted up. It is just starting to bloom for the first time. Photo by mrl2023.

Almost anything can be used to allow the leaf to grow babies, but I like to use small individual plastic pots. Rather than buying these, I use small plastic bathroom cups. You will need to poke a hole in the bottom for drainage. Do not make it too tiny as you want the water to drain quickly.  Use the same potting mix described above. I like to take a pencil and poke a hole in the mix.  This allows you to easily bury the stalk of the leaf, called the petiole, in the mix so that the blade is just above the surface. If the blade is touching the surface or below the surface, many times the leaf will rot before babies appear. As the leaf has no roots yet, care will need to be given to ensure it does not dry out. If you are only propagating a few plants, you could loosely place a sandwich bag over each cup. If you have a number of leaves you are propagating, then you could use a plant tray covered by a humidity dome. I prefer the taller kind with adjustable vents on the top and sides to allow some air movement.

Newly propagated African Violet leaves. Photo by mrl2023.

Plant cells are totipotent. What that means is that even though the cells have differentiated into specialize cells (like stem, leaf, root, etc.), they can de-differentiate and then grow into a whole new plant. This is different from animal cells where once they differentiate (specialize), they cannot go back. There are a few exceptions, of course, but it is beyond the scope of this article.  Scientists are trying to figure out how to make our cells do this so we can regrow limbs and organs. Anyway, back to our plants! The leaf cutting will end up sprouting roots, and eventually will grow new baby plants. Your one leaf may grow a new plant, but many times it grows a number of them. Once large enough to handle, you can separate these into their own pots.

A plant tray covered by a dome to increase humidity. Photo by mrl2023.

Care for your young violets is similar to the adults. Water when the surface is dry, but a bit more at the beginning before the roots form. Once the baby plants emerge from the soil, I start the diluted fertilizer regime. Don’t be too concerned at this stage with getting water on the baby leaves. For some reason, wet leaves do not seem to be a problem when the plants are young, but try to minimize this as a precaution. They should be placed in bright light out of direct sun.  Alternatively, you could place them under a lamp, or some fluorescent strip lights. Any of the new LED style lights meant for growing plants will work too, but the blue and red light will not show the true colors of the flowers. Daylight “colored” bulbs tend to show the flower colors the best.

Powered rooting hormone. Photo by mrl2023.

Once the baby plants get big enough and start to spread their leaves horizontally, remove the dome as the excess humidity will start to hinder their growth. I am going to say the plants are about one eighth to one quarter as big as the adults at this time, but you will need to use your judgement. Each home or growing area has its own set of environmental parameters. Once the plants are big enough, you can split them out into their own pots. You might want to use the small plastic cups again at this stage, and as the single plant gets bigger, move it up to progressively larger pots. Usually, most adult African violets end up in four-inch pots. I have seen some gigantic specimens in six-inch pots, but those are rare.

Hopefully this article inspires you to try your hand at propagating African violets. The best way to start is to go buy a nice looking one from a grocery store florist. These tend to be economical, but well cared for. A floral shop is also able to get some really nice, high quality plants if you desire. Many times, they will take requests for specific colors too. I find African violets make great birthday gifts. They are also nice to bring if someone invites you over for dinner, or just to pass around to family and friends for absolutely no reason at all. A word of caution, African violets are addicting. There is always another cool looking color or pattern to be had!

Happy Propagating!

Matt Lisy

Living in an 1840s house limits the amount of sunlight available to both occupants and houseplants. Windows are small and not especially numerous as back then, they would be seen more as energy/heat wasting units than as illuminating elements. For years, I have been bringing houseplants to work at the UConn Soil Nutrient Analysis Lab as the lighting, both internal and external is vastly improved when compared to what I could offer at home.

Trying to be restrained but yet being a plant nerd has been a hard dichotomy to attend to. Oh, what a gorgeous plant, I simply have to have it! No, you have no place in your house where it can grow! The two things I desire in my next home are a garage and plenty of windows.     

Last weekend, my sisters and I took a ride to Logee’s in Danielson, CT. They have several greenhouses filled with tropical plants, many in full bloom lighting up the cloudy, cold winter day. Logee’s has been around since 1892. It began as a cut flower business started by William D. Logee. He became enraptured with both tropical and unusual plants. In 1900, he purchased a Ponderosa lemon from Philadelphia and planted it in his greenhouse and 123 years later, it still is growing and producing huge lemons today!

Logee’s sign. Photo by dmp2023.

His son Ernest carried on his passion for collecting, selling and breeding exotic plants and ended up being one of the founding members of the America Begonia Society. You will notice quite the begonia collection at Logee’s. Although Ernest Logee died at a young age, his sister, Joy married Ernest Martin so they became second generation owners of Logee’s. Now their son, Byron, heads the third generation of growers and their offerings of exotic houseplants, hardy and indoor fruiting plants and unique introductions just keep expanding.  

There’s never a bad time to visit a greenhouse or garden center in my view, but something about getting up close and personal with a tropical plant clothed in showy blossoms during dismal winter days, just feels good. Two of my favorite vining plants under glass are bougainvillea ‘Orange Ice’ and blue skyflower (Thunbergia latifolia). Both need much more light and room than I can presently provide, but someday….

Bougainvillea ‘Orange Ice’. Photo by dmp2023

Citrus are another group of plants I like to try if I had more light. Logee’s offers Ponderosa lemons from cuttings off of the original Philadelphia lemon tree as well as other lemon varieties, several selections of oranges and limes, kumquats, guavas, figs and other tropical fruits that I am not familiar with. They look great here and if you have great light, do give them a try.

Ripening oranges. Photo by dmp2023.

Me, I am interested in some low light plants that I could grow in north windows as they are the only spaces free, at the moment. For years I have had a philodendron or two, the old-fashioned type with the heart shaped leaves. Not very exciting but they manage to survive with little care and low light levels.

I was delighted to find some choice philodendron selections at Logee’s. ‘Moonlight’ is a handsome chartreusey philodendron with bright lime green, new foliage, darkening with age. It has a more erect growth habit forming more of a 2-foot high and wide clump rather than climbing or trailing.

Philodendron ‘Moonlight’. Photo by dmp2023.

Another exciting find was philodendron, ‘Prince of Orange’. This plant also is more of a clump former with about the same dimensions as ‘Moonlight’ The leaves are quite unique as they change from sort of a golden yellow when they first emerge to a warm copper and eventually to a deep green.

Philodendron ‘Prince of Orange’. Photo by dmp2023

Philodendron ‘Cebu Blue’ looked quite interesting with its soft, steely blue leaves. It would look quite nice in a hanging basket. Upon further inspection, however, it turned out to be Epipremnum pinnatum, a similar-looking species and it was in its juvenile form. As it matures the leaves are bigger and split, like Monstera. At 4 feet in height, this plant will have to wait until I have more room, or I could bring it to work!

Philodendron ‘Cebu Blue’. Photo by dmp2023.

Even if you don’t bring home any plants, a visit to a local greenhouse or garden center on a cold winter day brings some of spring’s warmth into your heart and soul.

Dawn P.  

Red Raspberry (Rubus idaeus) is a perennial crop.  There are two types of canes in red raspberry plants. Primocanes are first year canes. Some varieties of raspberries produce berries on primocanes and are commonly called fall-bearing or primocane-fruiting raspberries. Other types of raspberries do not bear fruits on the first-year vegetative canes, but they develop flower buds that overwinter and produce berries in the subsequent season. These overwintered buds-bearing canes that will flower and fruit in the subsequent season are referred to as floricanes. After harvest, floricanes are commonly removed and the next cycle of primocanes develops. Sufficient nutrient availability during growth stages of red raspberry is essential for plant vigor, yield, fruit quality, fruit maturity, and sustainable plant health. Nutrient cycling in the soil-plant-air system in perennial plants is complicated and sufficient nutrients should be available before rapid nutrients uptake and requirement growth stages.   

Everbearing raspberries before pruning. Photo by dmp2006

Like any other plants, red raspberry requires seventeen essential nutrients, nine macronutrients (hydrogen (H), carbon (C), oxygen (O), nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S)) and eight micronutrients (iron (Fe), copper (Cu), boron (B), manganese (Mn), molybdenum (Mo), zinc (Zn), chlorine (Cl), and nickel (Ni)). The three most abundant essential nutrients (hydrogen, carbon, and oxygen) are predominately obtained from water and carbon dioxide in the air, while all other essential nutrients are taken up by plant roots from the soil. When the soil is unable to supply sufficient nutrient(s), fertilization is needed for optimum yield and quality of berries. Nutrient application should be based on soil and plant analyses and grower experience in their raspberry production system.

Bowl of Heritage raspberries. Photo by dmp2014.

Plant tissue analysis is an excellent method for growers to monitor nutrient sufficiency levels. Timely plant tissue analysis is helpful for detecting nutrient deficiencies in perennial fruits before visual deficient symptoms show up and minimize loss of yield and quality. Nutrient uptake, accumulation, and relocations in plants are complicated in perennial crops like raspberry, therefore, tissue testing should be based on a consistent sampling in the plant growth stage and time of the day, selection of the appropriate plant part, and the recommended sufficiency levels (please contact UConn’s Soil Nutrient Analysis Laboratory, www.soiltesting.cahnr.uconn.edu for the recommended sufficiency levels) for comparison.

Red raspberry growers are recommended to sample and test leaf tissue from all fields annually.

  • When to sample: Tissue samples should be collected when nutrient concentration is stable, thus, collect red raspberry leaf tissue mid-summer.
  • What part of a plant to sample: Collect approximately 50 of the 4th fully expanded leaves located about 12 inches from the tip to make a composited sample for tissue analysis. Collect leaves that are free of disease or other damage. A single composited sample should not represent an area of more than 5 acres. Do not mix leaves from field locations with different soil types or management histories. Separate samples should be taken for different soil types, management histories. For diagnosis purposes, separate samples should be taken in healthy and unhealthy plants.
  • How to handle samples: Put a composited sample consisting approximately 50 leaves in a paper bag, clearly labeled the bag, and send it to a local laboratory providing leaf tissue nutrient testing services as soon as possible. Conventional laboratory plant tissue nutrient analysis procedures are shown below.
Schematic flow chart of conventional plant tissue nutrient analysis procedures.

How to guide fertilization with laboratory results?

Compare the laboratory results to the recommended leaf tissue sufficiency levels shown in Table 1. If laboratory results are below the recommended sufficiency levels, fertilizer applications would typically be increased. If laboratory results are within the recommended sufficiency levels, continue with the current fertilization regimes. For recommended sufficiency levels please visit the UConn Soil Nutrient Analysis Laboratory or refer to University of Vermont Extension publication at https://www.uvm.edu/vtvegandberry/factsheets/tissuetest.html. To assist with interpretation of tissue analysis data, record keeping is recommended. In addition to keep records of tissue testing, soil testing results, weather (daily rainfall and temperatures), disease problems, nutrient application rates, form and timing, plant growth (such as cane number and height), yield, leaf color, and fruit quality are also helpful in estimate nutrient requirements in various crop yield potential situations.

Table 1. Recommended leaf tissue nutrient sufficiency levels for red raspberry.

NutrientSufficiency level
N (%)2.3–3.0
P (%)0.19–0.45
K (%)1.3–2.0

Dr. Qianwen Lu, Graduate Research Assistant, University of Connecticut