Wednesday, December 19, 2007

I had a great time being on the Mike Nowak show, “Let’s Talk Gardening” on WGN on Sunday. Young Pamela went with me as navigator and between the two of us we were able to answer a lot of questions. There was one question we didn’t get to that I would like to address.

A caller asked about a poinsettia she bought that had droopy leaves that watering didn’t correct. If you have a poinsettia with droopy leaves water it thoroughly but if it doesn’t recover within a few hours, then you have some other problems. Often poinsettias bought from a chain store have been subjected to several stressors. They may have been sleeved in plastic, subjected to long warehousing and transportation times in the sleeve, or have been stored in colde
r than optimal temperatures. The natural reaction by the plant in trying to survive is too droop its leaves and curl them in. Sometimes this is successful, sometimes not. Setting them in a sunny window so that the soil and their roots warm up sometimes helps. Don’t set them over a heating duct but do keep an eye on them since exposure to sun will cause them to take up lots of water and they may need another drink sooner than usual. We had that situation here in our greenhouses yesterday. After how many days of cloudy weather, the sun came out and really warmed up our greenhouses. Everyone was on water patrol to make sure all the plants got a drink!

Remember that poinsettias do best in cooler temperatures and, being desert plants, don't like to be watered frequently. A quick test for watering is to just pick up the pot and feel how light the pot feels. If it feels heavy it doesn't need to be watered. People ask us all the time how often to water but there is no easy answer. If it is sunny out and the plant is actively growing, it will take up water much faster than if it overcast or cloudy.

Sunday, December 16, 2007

Christmas Cactus

Native to Central and South America, Christmas cactus are actually epiphytes, plants that grow above ground level and rely on other plants to hold them up. About half of the 20,000 species of orchids are epiphytes, as are some lichens and algae. Learn something new everyday, don’t you.
Christmas cactus are similar to poinsettias in that they are short day plants that require long periods of uninterrupted darkness in order to flower. They also like cooler temperatures. Ann Larson in our interior plant department says that she gets great blooms from her cactus by leaving it outside at night when the nighttime temperatures are around 40-45 degrees for several nights.

As with most tropical plants, Christmas cactus require humidity to do well. This can be accomplished by placing the plant in a saucer filled with pebbles and water. The pot should be above the level of the water, but as the water evaporates it will provide the needed humidity.
After the plant has bloomed, give the plant a rest by placing it in a cool room with limited watering. After a month, repot if necessary ( they do like to be slightly root bound). If you need to pinch it back, do it in March or April when the new growth begins.

Friday, December 14, 2007

More Winter Blooming Plants

This is another great winter plant, not only because it blooms in the winter but the blooms are numerous. It can be a little fussy and most of the information I have been able to gather indicates that most people just pitch the plant after it has finished blooming.

As with most house plants they do need more humid conditions, especially when our furnaces are running and drying out the air. Get a plastic saucer and fill it with pebbles and water so that the water will evaporate and humidify the air immediately around the plant. The pebbles will keep the plant from actually sitting in the water. They also prefer cooler conditions and bright, indirect light. We were in Rome several years ago in January and I was surprised to see cyclamen growing outdoors in containers.

Cyclamen are tuberous plants and to get them to re-bloom they will need a dormant period after flowering. Let the plants die down by reducing and then stopping watering. Let them rest in a cool, dark place for three months, then re-pot and begin watering and fertilizing.

Norfolk Island Pines

Often called a "living Christmas tree," these plants hail from the South Pacific and are not pines at all. Norfolk Island Pines need bright, indirect light and do best in cooler temperatures. Plant them in a good, well draining soil mix and water to keep it slightly moist but not soggy. In the summer, fertilize monthly with a half strength general purpose house plant food. In the winter provide humidity by misting or setting the container in a saucer filled with pebbles and water. They like to be slightly root bound so repot only when necessary, every 3-4 years, in the spring.

Thursday, December 13, 2007

More Christmas Plants

Last week I blogged about poinsettias, probably the most iconic of Christmas plants, but there are other plants that come into bloom during the dark days of winter and amaryllis is one.

When selecting amaryllis bulbs, big actually is better. The bigger the bulb, the more stored energy, the bigger the bloom or blooms. Use a heavy container, since the full grown amaryllis can get rather top heavy. The container should be large enough to hold the bulb and a small space for a stake to be slid down beside the bulb but no larger. Plant in a good potting soil, burying the bulb so that only the top 1/3 is exposed. Water thoroughly but don’t let them get soggy. Within 4-8 weeks you will have blooms. Keeping the plant in a cool room will prolong the bloom period. A warmer room will accelerate blooming.

Amaryllis plants are easy to keep for the next year and as the bulb matures the blooms will only get bigger and better. Just follow these simple steps: Once the flowers have faded, remove the flower stalks but leave the leaves. Just as with our spring bulbs, this is how the plant replenishes the energy needed to produce blooms the following year. Fertilize with a general purpose house plant fertilizer on a regular basis. Choose a fertilizer that has a low first number (nitrogen) and higher second and third numbers (phosphorus and potassium.) You can also set the plants outside during the summer in a spot that gets afternoon shade. Leave the bulbs in their container as they do like being somewhat root bound.

Assuming you want the plant to rebloom at Christmas, prepare the plant for a dormant period. Stop fertilizing and reduce watering in August. After a few weeks, stop watering altogether. After the leaves have died back, remove them and place the container in a dark, cool place for 6-8 weeks.

In November, bring the plant back out to a warm, bright room and begin watering again. Within 4-8 weeks you should have blooms. Rotate the plant so that the stem grows straight as they have a tendency to grow towards light. You may have to stake it as well.
There are several reasons the bulb may not rebloom the second year including not enough dormant time, or leaves were removed before the plant stored enough energy over the summer. In this case make sure to let the plant get enough sun and fertilizer during the actively growing months to let it store enough energy to bloom. When you do need to repot, you may notice little bulblets. You can plant these and follow the above directions, but amaryllis bulbs take several years to get big enough to bloom, but it will be worth it!

Just to let you know I will be discussing plants for Christmas on the Mike Nowak show on WGN on Sunday, December 16. Be sure to tune in.