Freeze Protection for Plants

Written by Anna Land, AZH Certified Zoo Horticulturist & Houston Zoo Horticulture Supervisor

The Horticulture department at the zoo cares for 55 acres that are covered with a very diverse collection of plants, which makes winter protection a team effort.  We’ve been keeping our eyes on the forecast and have made sure that we’re ready with frost cloth when the time comes, which looks like it may be this weekend.  With the possibility of a freeze tonight, I’ve had several staff and Zoo Members ask me the best way to protect their plants at home.  So I thought I’d share some information on freeze protection.

hibiscus rosa-sinensisHere in Houston, we’re able to grow many tropical plants which have not evolved to deal with freezing temperatures.  For them, when temperatures get down to freezing, ice crystals will form in the cells within the leaf.  These crystals pierce the cell walls of the plant, as the temperatures rise and the ice melts, holes are left in the cell walls causing the fluid to leak.  This results in the mushy tissue you see after temperatures warm up.

To prevent this, you want to keep the temperature around the plant above freezing.  There are several methods that can be used, but the easiest way to do this is to make the radiant heat coming from the ground work for you.  Properly covering a plant with frost cloth or a sheet* will trap that radiant heat and hold it around the plant, keeping it above freezing in most cases. Extended freezes or extreme cold may require additional methods to be used, but when temperatures stay around 32⁰F during overnight hours, covering is sufficient.  To properly trap the heat you must bring whatever covering you’re using all the way to the ground and secure it so that you don’t have cold wind blowing through and pushing warmer air out.  This can be done with rocks, stakes, turf staples, or even toys the kids left in the yard… whatever is small enough to move and heavy enough to withstand wind.   Potted plants can be covered in the same way, moved into a garage or covered area, or even moving them up against the house and giving them a good watering will help.

Driving around town over the years I have seen many trees wrapped like lollypops, this does not trap radiant heat and doesn’t do much for your tree other than turn it into yard art.  If you have a newly planted tree that the crazy weather has caused to start pushing out new leaves and you want to protect them, you can wrap your tree like that, but you will need to provide a heat source inside that covering.  An example would be outdoor rated incandescent tree lights, but make sure you follow all recommended safety guidelines; you don’t want to turn your tree into a candle.

freeze protection

A quick note about frost cloth vs. sheets:  Frost cloth was originally designed for production agriculture, so it’s designed to trap the heat and allow light through and won’t absorb water. This allowed those growers to cover their plants and leave them covered, saving time and labor costs.  This means that if you’re using frost cloth and the forecast calls for multiple nights with freezing temperatures, you can leave your plants covered for extended periods of time.  On the other hand, if you are using sheets to cover your plants, you will need to uncover them during the day once temperatures have risen above freezing.  There are a couple of dangers with leaving sheets over plants for extended periods of time: 1) the plant may not get enough sun light; 2) if the sheet gets wet it could provide conditions for fungal/pest problems; or 3) it could get warm enough underneath to encourage the plant to start growing at the wrong time.

*I don’t recommend using plastic sheeting unless it’s on some sort of framework preventing it from touching the plant.  Laying it directly on a plant can still allow freeze damage and if not removed as temperatures warm, can  “cook” your plant as it accumulates the heat from the sun.



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This morning, we humanely euthanized our male, 20-year-old jaguar, Kan Balam. Due to the tremendous care provided to him by his keepers and our veterinary team, Kan Balam lived well beyond his expected lifespan. Jaguars expected lifespan in the wild is between 12-15 years.

The carnivore staff and veterinary team made the decision after his quality of life began to decline. Quality care and continuous advances in veterinary medicine extends animals’ lives longer than ever, with most felines in human care living well beyond previous generations. Because of this, all cats, including domestic house cats and jaguars, often spend a significant phase of their lives as older animals, and are at a higher risk for geriatric complications.

Read more about Kan B, and the love his keepers had for him on our blog: www.houstonzoo.org/blog/mourning-loss-geriatric-jaguar-kan-balam/
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This morning, we humanely euthanized our male, 20-year-old jaguar, Kan Balam.  Due to the tremendous care provided to him by his keepers and our veterinary team, Kan Balam lived well beyond his expected lifespan. Jaguars expected lifespan in the wild is between 12-15 years. 
 
The carnivore staff and veterinary team made the decision after his quality of life began to decline. Quality care and continuous advances in veterinary medicine extends animals’ lives longer than ever, with most felines in human care living well beyond previous generations. Because of this, all cats, including domestic house cats and jaguars, often spend a significant phase of their lives as older animals, and are at a higher risk for geriatric complications.

Read more about Kan B, and the love his keepers had for him on our blog: https://www.houstonzoo.org/blog/mourning-loss-geriatric-jaguar-kan-balam/

 

Comment on Facebook

Soft kitty, warm kitty, little ball of fur; happy kitty, sleepy kitty, purr purr purr #RIP #bigbangtheory

I know he lived a lot longer due to the excellent care he got at the Zoo.

Is this the one that had the limp?

Sorry to hear about your loss. We also lost a jaguar(melanistic variety) at Reid Park Zoo about a year ago. Nikita was 21 years old and was euthanized due to health-related issues. Sad, but they have a GOOD life at the zoo! No predators, a steady food supply, medical attention, loving kindness from her keeper(s) and admiration by the public. Geriatric animals have unique problems and we are blessed to get to know them as long as we do.

This was my daughters favorite critter at the Zoo. We always went to say hello to him before anyone else whenever we went. When she was 7 years old we sent a post out to out neighborhood on Halloween saying Paisley was asking for pocket change donations in lieu of candy for Halloween and all amounts would be donated to Kan thru the zoo. She raised over $40 in coins! I still have the letter from the zoo thanking her for her donation. He was a sweet boy and will be missed. 😔

I saw him limping about 2 weekends ago. The first time we walked by he was fine. When we walked by on the way out he was limping and moaning pretty loudly. I wondered what happened but I figured his keeper already knew or would find out shortly. Super Sad. He was always a lively one.

Jaguar habitat is in the Zoo or Jungle's? ??or is only entertainments for person's? ??$$$$$$$!.Sorry animals the person's don't love you ..

Sending love to the keepers that are broken hearted right now. And thank you for all the care you’ve given.

Dunno if the Zoo staff considered him a pet but he was certainly a family member, and because of that i offer this: RainbowBridge Author Unknown Just this side of heaven is a place called Rainbow Bridge. When an animal dies that has been especially close to someone here, that pet goes to Rainbow Bridge. There are meadows and hills for all of our special friends so they can run and play together. There is plenty of food, water and sunshine, and our friends are warm and comfortable. All the animals who had been ill and old are restored to health and vigor. Those who were hurt or maimed are made whole and strong again, just as we remember them in our dreams of days and times gone by. The animals are happy and content, except for one small thing; they each miss someone very special to them, who had to be left behind. They all run and play together, but the day comes when one suddenly stops and looks into the distance. His bright eyes are intent. His eager body quivers. Suddenly he begins to run from the group, flying over the green grass, his legs carrying him faster and faster. You have been spotted, and when you and your special friend finally meet, you cling together in joyous reunion, never to be parted again. The happy kisses rain upon your face; your hands again caress the beloved head, and you look once more into the trusting eyes of your pet, so long gone from your life but never absent from your heart. Then you cross Rainbow Bridge together....

Thank you Houston Zoo for taking such good care of him and all the animals! I've been going to this zoo since I was little bitty. I always enjoy it.

Aww. When interning in the carnivore dept he was one of my faves. So smart! Ashley remember when Angie was teaching him to do the moonwalk after Michael Jackson passed?

Beautiful jaguar ....so grateful for the Houston Zoo keepers and veterinary team that gave their time and efforts to share this awesome jaguar with us for so many years.

He was well-cared for and most of all well-loved. My heartfelt condolences to those missing Kan B as well as me. What an amazing ambassador for his kind. What a beautiful old gentleman. Thank you for loving him into old age and giving him peace.

What a great long life he lived because of his excellent care at the zoo Thoughts go out to his keepers and the entire Houston Zoo staff

Thank you for doing what was right and kind for Kan Balam even though it was hard and painful for you. That’s true love for an animal. ❤️

RIP Kan Balam. You have given the visitors so much pleasure just watching you over these years. You were taken care of by top notch professional handlers, etc.

Aww I’m so sorry for the loss, I’ve seen him many times, he was absolutely gorgeous! I’m glad that you guys were able to make him comfortable, sometimes the best thing we can do is let them be at peace. Will miss this handsome guy; play hard at the Rainbow Bridge friend, day hi to my cat, Junior for me!! Much love to the HZI staff!!

I'm so sorry for your loss. Thanks for taking such great care of him so he was able to live a long life. My thoughts are with his keepers and all who adored him. <3

Jaguars are one of my favorite and he seems like a sweet boy. I'm so sad but I'm happy he can be painless and be free now. RIP❤️

The Houston Zoo staff has lost several animals this year and I am sure each one is so hard to go through.

I am soo sorry for the loss of this handsome fella Kan Balam. May he rest in peace and run free or any pain over the rainbow bridge.. My heart and prayers go out to each and every one of the staff at the Zoo.

Katie Rose Buckley-Jones I won’t ever forget the time you asked him to bring something and he ripped off a piece of cardboard and tried to hand it to you ❤️ thank you for introducing me to him. Sending you guys many hugs

So sorry to the keeping staff for your loss i cant imagine how youre feeling :( his old age is a testimony to the amazing care he received

I will miss him. The last time I saw him he looked tired, and it appeared his foot was bothering him.

Sad to hear of this. Thanks for taking such good and compassionate care for him and the other animals.

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Social Media Guy to Sea Lion Keeper: Can you send me a pic of you working with the sea lions in this chilly weather?

Sea Lion Keeper: Sure... (sends picture next to sea lion statue)

SMG: I'm still using this.
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Social Media Guy to Sea Lion Keeper: Can you send me a pic of you working with the sea lions in this chilly weather?

Sea Lion Keeper: Sure... (sends picture next to sea lion statue)

SMG: Im still using this.

 

Comment on Facebook

Are there some zoo animals that enjoy this weather?

SMG is another reason why Houston Zoo is the best Zoo!

Happy New Year “sea lion keeper “ 💖💖

More snow for TJ and Max ❤️ lucky them!

Are we positive that’s the statue rather than it really just being that cold? 😛

That’s my best friend Sophie for ya! 😂

Brrrrr

Omg the Zoo is so awesome 😂😂😂 Alana Berry

Omg be warm sweetoe

Haha!! Good one!

Sweetie 💞

Ashley Jucker 😂

Lauren Gonzales

Mike DePope

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