Monthly Archives: January 2013

Desert in Bloom

cactus in bloom

Mammillaria species (Cactus family) in the Conservatory.

The Cactus and Succulent collection at the Horridge Conservatory contains a wide variety of beautiful plants. You may or may not know that a Cactus is a certain family of plants –the Cactaceae. All Cactus are succulents, but not all succulents are Cacti! A succulent is a broad category of plants which have thickened and fleshy leaves and stems, usually to retain water in  arid climates and soils. Most succulents come from dry regions of the tropics and sub tropics such as steppes, semi-desert, and desert. High temperatures and low rainfall force plants to collect and store water to survive long dry periods. Many succulents (including Cacti) are grown as ornamentals or houseplants because of their unusual and interesting appearance. Familiar succulents include  Jade plants (Crassula ), Aloe plants (Aloe ), or Mother-of-Millions (Kalanchoe).

gasteria flower

Gasteria armstrongii in bloom.

Cacti are for the most part native to the Americas, ranging from Patagonia in the South to parts of western Canada in the north. Most cacti live in very dry habitats subject to at least some drought. Cacti show many adaptations to conserve water. Most species of cacti have lost true leaves, retaining only spines, which are highly modified leaves. As well as defending against herbivores, spines help prevent water loss by reducing evaporation.  Cactus spines are produced from specialized structures called areoles, which are an identifying feature of cacti. Other types of succulents, such as Euphorbias, have spines but do not have areoles.


Golden Barrel Cactus, Echinocactus grusonii, with Paddle Plant, Kalanchoe thyrsiflora.

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Trailing Kalanchoe

The lengthening days of late winter and early spring is when many of our cactus and succulents bloom, just as in the desert. I love to see them at this grey time of year. Some, such as the Gasteria and Aloe, come in a range of sunset colors (like the Echeveria from this post.) Some are bright pink or purple and others are pure white. If a trip to the Arizona or New Mexico isn’t possible, come visit our little desert at the Horridge Conservatory.


Another Kalanchoe –Kalanchoe gastonis-bonieri


Mammillaria species in bloom.

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Two Aloe plants in bloom.

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frost in conservatory

Sunlight hits frost on the windows inside the Horridge Conservatory. Temperature outside was 5 degrees F.

Greenhouse scouting: Integrated Pest Management – IPM – relies on information gathered through scouting, or monitoring,  to make decisions about which pest control measures should be taken. I wrote about our greenhouse IPM program in this post last winter. I am happy to report that there are fewer, much fewer, insects than last winter. Of course, there are the usual “bad guys” — but not so many.

From the Ohio State University Extension:

“The person who performs the field scouting activity in an IPM program is referred to as the “field scout.” This individual is responsible for collection of field observations and may or may not be responsible for making pest management recommendations. In some IPM programs, it is the field scout’s role to collect field observations but not provide recommendations.

The tasks of the field scout include (1) making accurate identifications of pests and related crop injury present in the field, (2) determining the abundance of the pest populations and degree of injury present, (3) noting relevant parameters related to crop development, and (4) recording all field observations in a manner that can be forwarded to the party making the final decisions regarding pest management actions to be taken.”

I have been scouting the greenhouses each week — systematically going through each one, looking for anything out of the ordinary. We tend to have insect pests but very little in the way of diseases through the winter in our greenhouses. Once I get a good picture of which pests are present, I can make decisions about what management or control strategy to use. The IPM approach means that we start with the “least toxic” methods, which is often as simple as a soap and water spray.

Last winter’s application of Steinernema feltiae, a microscopic nematode which attacks  the larvae of Western Flower Thrips, has resulted in a lower population of thrips this year. Cabbage worms (A strange thing in the greenhouse in January!) on the coleus are big enough to hand pick into a bucket of soapy water. For insects such as scales and mealybugs, ultra refined oil spray is an ecologically good choice because it’s mode of action is mechanical (the thin coating of oil smothers the insects) rather than chemical. This means that pests cannot develop resistance to it. It is also much safer for the greenhouse staff and visitors.

Scouting is part of the fun of working in the greenhouse. I enjoy the detective work of identifying what is causing problems for the plants, whether it is insects, disease, or environment. Then figuring out what can be done — taking action always feels good. And finally seeing the healthy plants with renewed vigor and growth is very rewarding to me!

Here Comes Sunshine

It’s a January thaw and that means time to get outside and prune, or even cut down trees. Back in August I wrote about taking down trees along the shady firelane adjacent to the greenhouses. Now it’s time for the trees behind those to be removed — this will truly improve the amount of sunlight getting into the greenhouses. Our Tree Guy/Greenhouse Manager, Nick, was kind enough to wait until I had moved the more delicate shade plants  and until the ground was frozen before he started trampling all over the garden!

cutting tree

First, cut….

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Then PULL….



Although there is a beautiful shade garden there,  I am not sorry to see the trees go. The perennials will be moved to new homes in other parts of the Garden, and the more adaptable ones may be just fine with more sun. After all, it will still be on the north/shady side of some VERY impressive Rhododendrons.  What I will miss is the tunnel effect of the trees over this little stone walkway between the firelane and the rose garden, which always looked to me like something from a fairy tale.

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Looking out across the newly opened view of the garden from the greenhouses, I think the garden appears  smaller now. Having a hidden area tucked away to discover, on the other side of the trees, made it seem like it might be much bigger. (It’s actually not very big — about 4 ½ acres.)

But in the spring…there will be the fun of putting in a new garden, or at least planting a few new things!  Maybe a Viburnum carlesii,  with delicious sweet flowers to brush by. Maybe a trellis to frame the walkway,  or some sculptural Garden Art…maybe a garden designed by a student….stay tuned!

A New Year

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Happy New Year!

Here in Rhode Island, the new year is starting off with the coldest weather we have had in quite  while: 12 degrees F this morning. We also have snow, which we didn’t have last year. The Garden looks beautiful under it’s frozen white blanket. Tiny tracks of mice, rabbits, and squirrels can be seen in the snow,  under sheltering evergreens or bravely crossing an open expanse of small-scale tundra.

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In the Conservatory, it’s warm and inviting.  Sun beaming through the glass and green leaves of every size and shape are a welcome change for folks tired of the cold.  I enjoy all the seasons but it is nicer to work in the warm Conservatory in January than it is to work outside!  Some plants are growing very slowly because of the short days, while others burst into bloom at this time of year.

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The latest newsletter from the National Garden Bureau has a short list of  New Year’s Resolutions for gardeners. I’ve always thought that ANY day could be the day I decide to change something in my life — no need to wait til January 1st! And for gardeners, perhaps the first day of spring is a good time to make a Gardening Resolution. Nevertheless, here they are:

1. I will not blame myself for gardening failures. Sometimes, Mother Nature is not our friend when it comes to gardening. Or life gets in the way. Don’t despair! Simply try again and learn from experience. Your garden, and your gardening friends, are very forgiving.

2. I will not be afraid to ask questions. How else can you learn? Take advantage of the experience of your neighbors, friends, and family. They will appreciate your interest and be flattered that you want to learn from them. And learn you will!

3. I will try something new. This is kind of a no-brainer, right?

4. I will share my passion. We’ve done and seen studies that show many of today’s gardeners got their start by learning from someone else, usually a parent or grandparent. Can you be that mentor? Will you be the reason your son or daughter serves homegrown vegetables to your grandchildren? The reason your neighbor plants window boxes for the first time?

5. I will embrace nature and garden for the birds, the bees and the butterflies (and the bats too!). One of the most enjoyable benefits of having a garden is being able to see the beautiful creatures who visit it. So plan your flowers and vegetables with that in mind then sit back and watch the wildlife you’ve encouraged.

And of course, resolve to visit the URI Botanical Gardens and Horridge Conservatory in 2013!

Do you have New Year’s Resolutions?  Or Gardening Resolutions? I’d love to hear from you!

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