Category Archives: Light

‘Tis the Season … for Poinsettias!

By Cheryl Harrison, Master Gardener

When I was growing up, my mother always had a big green and red poinsettia sitting in the centre of the dining table during the holiday season. By the middle of January, it had lost all of its leaves so out it went in the trash. Oh yes, we also called it a “pointsetta”.

In Mexico, where it grows wild as a leggy shrub or small tree, the native plant (Euphorbia pulcherrima) has been associated with the Christian Christmas holiday since the 16th century. Thanks to Joel Robert Poinsett, the first U.S. Ambassador to Mexico, poinsettias were introduced to the United States in 1825. They did not really take off, though, until the California based Ecke family grew plants using a grafting technique discovered by Paul Ecke Sr. in the 1960s.  They began aggressively marketing the holiday season blooming poinsettia as a holiday tradition. In the 1980s, John Dole identified the technique used by the Ecke family to produce their compact poinsettias. This led to many more growers entering the retail market.

Poinsettias are members of the Euphorbia family. The brightly coloured “flowers” are actually bracts (modified leaves). Their bright colour helps to attract pollinators in the wild.poinsettia1

When purchasing poinsettias, look for an erect plant that has dark green leaves down to the soil and fully coloured bracts. The actual flowers, located at the centre of the bract, should be immature and red-tipped or green, not yellow with pollen because these more mature blooms will not last as long as the immature blooms. Plants displayed in plastic sleeves or crowded together may be stressed and deteriorate quickly after purchase. When purchasing any plant, always check for disease or insects. Yellow leaves, wilt or the presence of insects (check the underside of leaves too) always indicate problems and a plant that you do not want.

Poinsettias are not poisonous to humans but may cause pets to experience vomiting and diarrhea if consumed. Like all Euphorbia, damaged poinsettia stems and flowers exude a white sap that may cause skin irritation to susceptible individuals and pets.

There are over 100 varieties of poinsettias. They come in many colours from the traditional red to white, pink, cream and marbled or speckled.

Poinsettias prefer 6 hours of indirect light each day away from heat registers and cold drafts. Water the plant when it is dry but do not overwater because it may wilt and drop its bracts. (I think that is likely what happened with my mother’s poinsettias!) Allow the water to drain into a saucer after watering then discard this water. Do not let your plant sit in water. If you would like to keep your plant past the holiday season, fertilize it once a month with a houseplant fertilizer once the plant has stopped blooming.

Poinsettias may be put outside in the summer after all danger of frost has passed. But if you would like it to rebloom during the following holiday season, bring the plant back indoors before frost. Then, beginning in October, keep it in total darkness for 14 hours each night. The combination of total darkness and warm, bright days should cause the bracts to colour. This might be fun to try but to guarantee that you have a blooming poinsettia during the following holidays, purchase a new one and compost your old plant.

Poinsettias have long been associated with the holiday season. They come in several colours which will help to add holiday cheer to any home decor. Enjoy them while they last!

For more information on poinsettia care and reblooming, please see the links below.

Holiday Cactus Conundrum

by Emma Murphy, Master Gardener

Definition of conundrum
A confusing and difficult problem or question

Despite the shortening days and dark and dreary November weather, every year around this time I am delighted to see members in my various gardening groups posting photos of their “Christmas cactus” in bloom. The colours are many and varied – from red to pink to white to some lovely peach selections. People post amazing stories of plants being handed down from generation to generation and being over 100 years old.

The conundrum? They are generally not “Christmas cactus”. Since education is a big part of the role of Master Gardeners, I thought I would offer some explanation of the various types of indoor cacti we see here in Ontario (and Canada) and how to figure out what type of cacti you have!

There are actually three types of holiday cacti – all theoretically named for the time of bloom (although that gets messed up depending on whether you are north or south of the American/Canadian border!). The three types are:

  • Thanksgiving Cactus (Schlumbergera truncata)
  • Christmas cactus (Schlumbergera bridgesii [also S. buckleyi])
  • Easter cactus (Rhipsalidopsis gaetneri [also Hatiora gaertneri])
National Garden Clubs Inc.
Source: National Garden Clubs Inc.

They are all called “leaf cacti” because the plant bodies are flattened and the leaves are actually stems. These type of cacti are epiphytes from the tropical treetops of the rain forest and natural forests of Brazil and require similar care, even though they bloom at different times of the year. In their natural habitat, they grow on trees or rocks in habitats that are generally shady with high humidity, as opposed to their desert-dwelling cousins. So they don’t need bright sunlight and they don’t have nasty spines!

Most people have the Thanksgiving cacti, which bloom between November and January. Christmas cacti bloom in December, and Easter cacti in April/May.

thanksgiving cactus
Thanksgiving cactus

The leaf stems (and to some extent the flowers) tell you which type you have, rather than the bloom time. Thanksgiving cactus is often known as “lobster cactus” because the edges of the leaves are hooked, giving them a claw-like appearance. The Christmas cactus has leaf projections which are more scalloped or tear drop shaped. The Easter cactus has very rounded edges which are centralized on the leaf.

christmas-cactus-277691_1280
Christmas Cactus
EasterCactus
Easter Cactus

All three cacti are short day plants, so in order to induce the plant into bloom it must have 12 to 24 hours of darkness and cool temperatures. If you have put your plant outdoors over the summer or purchased it recently it should be kept in a cool, dark location until it sets buds. A seldom used bedroom or lower level is the ideal place. The Christmas and Thanksgiving cacti require approximately 6 weeks of short days in order to bloom (the Easter cactus requires 8 to 12 weeks to bloom). When the buds appear it can be brought into a warmer area. If it starts dropping buds it could be due to drafts, too-warm temperatures, too much water or direct sunlight.

FUN FACT! Unlike Christmas poinsettias, Christmas cacti are not toxic to dogs and cats, making this cat mum very happy.

Growing Tips

Since they are from the rainforest, they like acidic well drained soils. Use a cactus mix and add perlite, vermiculite and orchid bark. Do not overwater – why most of them die! Neglect is better than over watering. Water when the top 2 inches of soil is dry. Mist them frequently to increase humidity and fertilize them with a all purpose fertilizer. Those who hate repotting plants can take comfort in knowing that holiday cacti bloom best when they are slightly pot-bound and only need repotting every 3 or 4 years.

Common Problems

The most common issue you might face is dropping buds, which can occur when there is any type of change in the temperature, lighting, humidity, or the amount of water the plant is receiving. Try to keep the soil moist, the temperature a steady 15 to 20 degrees Celsius, no fertilizer in the late summer to fall months, and 14 hours of darkness each day. Other issues that could affect your cactus include stem rot (this fungal issue occurs when the soil is too damp – start a new plant before the infection spreads too far), root rot (happens if roots get soggy, so remove that root so it doesn’t go further up the stem, which might kill the plant), and Botrytis blight (which is grey mold and can be removed if discovered early).

When they have finished blooming, these cacti need at least two months rest. Give almost no water or fertilizer during this time. The Thanksgiving and Christmas cacti may bloom again in the spring, but probably with less (and smaller) blooms.

While holiday cacti appear to be a bit finicky, if you understand where they come from, and what they need to be happy, you may be able to successfully keep your holiday cactus for 100 years!

 

The Light in Your Garden

by Chris Freeburn, Master Gardener

Growing any plant successfully in your garden depends on many factors and an important one is the amount of light you get throughout the day. Growing Hosta out in the blazing sunshine is fine when they first emerge in springtime, but most Hosta will fry with the hot summer sun all day long. A peony without enough sun will have lovely green leaves, but will probably not give you any flowers.

Take a day or two to notice when your flower beds are in sun and for how long. Full sun means at least 6 hours of sun a day. Full shade means no direct sun. Part sun should only be about 3 hours. Morning sun is the best as it is not harsh and hot like late afternoon sun, so if you have gardens facing east, you have the best light for most plants.

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Knowing which direction your home sits is important too. Get your orientation fixed in your mind. Remember that trees and buildings will shade the gardens as the sun moves throughout the day. As the seasons change, the sun will move slightly in its orientation and where the sunlight comes from will change. Be prepared when you go plant shopping, read plant tags and talk to experts to be sure you are putting the right plant in the right place for the right light requirements.

Like growing just outside your garden growing zones, gardeners can also grow outside sun requirements. Hybridizing has enabled us to have plants that will grow outside their normal light needs. For instance, there are now Hosta that will take a lot of sun. Try to stretch the limits if you want that certain plant in that certain place, but remember to monitor it to be sure it is not being stressed and is performing at its best.

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Lighting may change in your garden. If a big tree is removed, a full shade garden can become a full sun garden. As a tree grows in your or your neighbour’s yard, or if a new building goes up, it will become more shaded. You may find that you will have to relocate plants when this happens.

Spend more time in your garden, just watching. It is good for your education and good for your soul.