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Hidden Valley Hibiscus
Growers & Hybridizers of Exotic, Tropical Hibiscus
Volume 13, Issue 10
October 2012

News from Hidden Valley Hibiscus

Exotic Hibiscus 'Satsuma'

Exotic Hibiscus 'Saffron' in Page Border

'Summer Romance'

'Peppermint Drop'

Happy Halloween Everyone!

Cooler weather has finally come for most of us. After a long, hot summer, we've had a beautiful fall with nearly ideal weather for hibiscus in many areas. But winter is just around the corner, and for some of you, it is already here. So it's time to start planning how to Get Our Hibiscus Ready for Winter. Our first article has tips for getting both indoor and outdoor hibiscus ready for winter.

Our second article, Those #$%& Gophers!!!!! may resonate with many of our fellow gardeners! A little bit of humor, a lot of frustration, and FINALLY, a solution! Read about Charles and Cindy's great gopher caper!

And of course, at the bottom of the newsletter, take a peek at our newest Seedling of the Month, 'White Hot.'

Our spookiest Halloween wishes to all!

Charles & Cindy Black

'Vein of Gold'

'Time for Love'


Getting Hibiscus Ready for Winter

'Golden Mist'
Even though October has many warm and sunny days that can be great for hibiscus blooms, it is time to start planning for the upcoming winter months. In this article we will review the important points to consider when overwintering hibiscus. We will start with potted plants and finish with hibiscus planted in the ground.


Potted Hibiscus Plants


Outside Preparations, Before you Bring Plants Inside

Before bringing hibiscus into warmer conditions there are a few things you can do to prepare them. First, consider pruning the plants. This has several advantages:

  • Pruning removes insects and insect eggs that may be living on the plants
  • Pruning reduces the size of the plants which makes it easier to fit them inside

'Venetian Pepper'
We only recommend pruning if the plants will be overwintered in a space that is warm and has adequate light. If the plants will be placed in a relatively cold and dark place, such as an unheated garage, then wait until next spring to prune. We consider a warm place to be one that has a minimum temperature of 60°F (15°C) and an average temperature above 70°F (21°C). In other words, the night temp should not fall below 60°F (15°C) and it should get warmer during the day. Adequate light is harder to specify but if you consider the area bright enough to read and do detail work such as sewing it is probably adequate. The longer light is available during the day/night the better the hibiscus will do in that location.

Whether the plants are pruned or not, it is important to move them to their winter location as free of insects as possible. The cheapest and most effective way to achieve this is to wash the entire plant, including tops AND bottoms of all leaves, branches, and stalks with a strong spray of water. You can use a BugBlaster or a hose with some sort of spray attachment that allows for lots of pressurized water to be directed at the leaves of the plants. If you find it challenging to get up under the leaves (this is what the BugBlaster does so well) you can always tip the pots over on their sides and then spray the bottom of the leaves. Turn the pot a quarter turn and spray the leaves again, and then another quarter turn and do it again. After turning the pot 4 times, all sides of the plants and all leaves should be very well cleaned. The plants should be cleaned in this manner several times before bringing them inside, finishing up on the day before moving them in or even the morning of the move.

'Electric Red'
In addition, potted plants can be treated with Safari, a long-lasting, systemic treatment that will help with all pests except for spider mites. Unfortunately, spider mites are the most persistent indoor pest and will cause the most damage to the hibiscus if allowed to multiply on the hibiscus. Mites do not tolerate water well and the washing treatment is very effective if you do it thoroughly and several times before bringing your plants indoors.


Moving Potted Plants Inside

The hibiscus are now ready to move into a protected environment. The choices are greenhouses, garages, basements, or any room in the house that has space for them. Overwintering hibiscus in environments that are barely sufficient to keep them alive is better than leaving them out exposed to freezing temperatures, but the plants will be set back and slow to recover the following spring. It is far better to arrange to keep them somewhere that the temperatures remain at 60°F (15°C) or above.

Greenhouses: These can be heated or non-heated. Unfortunately, non-heated greenhouses lose heat during the night until they are at, or within a few degrees of, the outside temperature. Unheated greenhouses are better than nothing because they warm up much more quickly once the sun is up than the outside does but, in winter, days are short and within a few hours of warming up the temperatures will once again drop lower than hibiscus need. In a place with hard freezes the hibiscus will not survive in an unheated greenhouse.

Heated greenhouses are excellent places for hibiscus to overwinter. Not only do the temperatures remain warm all night but the plants will get plenty of sunlight, sometimes enough to bring out winter blooms! Building a greenhouse is a big job, but we have help and tips in several places on our website, including our Building a Low-Cost Greenhouse page, and the Greenhouse section of our HVH Forum.

Garages and Basements: These have generally the same pluses and minuses as heated and unheated greenhouses. If the garage or basement is not heated and temps fall close to freezing on cold nights, the hibiscus may survive but will not flourish. However, if either space can be kept warmer, as close to 60°F (15°C) as possible, then the hibiscus can do very well. Such spaces will usually need to be equipped with extra light. You can use state of the art HID lights, multiple bulb higher wattage T-8 fluorescent lights, or just simple fluorescent shop lights will keep the hibiscus alive and well if the space is also well heated. The more light the plants get, the more likely they will bloom and grow during the winter. However, it does not take a lot of light to keep them green and healthy if, as we have said repeatedly, the temperatures are high enough.

Rooms in the House: This can be a great place to overwinter hibiscus. Mostly, hibiscus like conditions that humans like. If you are warm, they will be happy too. Most houses have windows that allow sunlight to enter the rooms during the day, but if your only available room is on the dark side, then just adding a few lamps can make all the difference. If a room is particularly dark you can add a couple of lamps and leave them on either all the time or for as long as you possibly can. It is the amount of cumulative light that makes a difference to hibiscus and most plants, so low light for a long time is as good as higher light for a shorter time.

'Corona del Mar'
We have learned to really enjoy having hibiscus in our living space during the winter. Our indoor hibiscus look pretty, clean the air, add oxygen to the indoor environment, and provide us with a steady stream of beautiful flowers during the winter. We don't get as many flowers as in the summer, but we do get some flowers in our living room, kitchen, and dining room which all have windows that let sunlight in during the winter months. You will want to set the plants in deep saucers so that watering is not a problem. These can be either cheap clear plastic ones available at the big box stores or nicer looking ones available at any garden center. For more information about growing hibiscus indoor, go to out Hibiscus as Houseplants page.

We no longer recommend that potted hibiscus be kept outdoors during the winter. There are a number of ways to try to keep them warm at night such as covering them with frost cloth or running water into the pots all night long when freezes are predicted, but these techniques are only barely adequate to keep the plants alive and should be used only as a last resort if the hibiscus cannot be brought into a more protected and warmer area for the winter.


'Red Cape'
Outdoor Hibiscus Planted in the Ground

In a few areas of the continental USA hibiscus can be planted in the ground and will survive most winters. This includes coastal southern California, along parts of the Gulf Coast states near the Gulf, and southern Florida. In the past we have observed that hibiscus in these areas will go mostly dormant and many of the plants will lose most of their leaves before winter is over. However, during the last couple of winters some dedicated hibiscus growers have reported not only continued growth but also many flowers on their outdoor hibiscus through the winter months. We've seen the photos of the plants during January and February and were very surprised and pleased to see the growth and the amazing profusion of blooms. This was achieved by spraying Supernova Growth Enhancer on the leaves of the plants several times per week. The hormones in this natural product counteract the cooler temperatures and maintain the plant in an active state of growth and blooming. For those of you who are interested in achieving this result we recommend that you read over the HVH forum for the months of January-March of 2012 to see the photos and read more about the techniques that were used to achieve them.



Those #$%& Gophers!!!!!

Photo courtesy of UC Davis
If you've ever engaged in battle with gophers, you have our deepest sympathy! We feel your pain, and our own pain too! For the last two summers, we have been waging a personal war against those little critters who are way too smart for our own good. Our three big dogs have done their best to help us as we tried every trick, tool, trap, bait, and strategy we read about in every website, university publication, pest control book, and gardening forum. But gophers are crafty little creatures, and even our dogs had difficulty getting to them.

Our problem was that they managed to eat almost everything we planted for two entire summers. We planted all our flowers in the ground in gopher-proof pots, and covered every inch of space around the pots with heavy landscape fabric. The gophers managed to tunnel under a concrete sidewalk, under the landscape fabric, up to the edge of the pots to find a teeny spot to push the fabric up enough that they could crawl up into the pots to chew big branches off each plant. The branches were so big that they couldn't even eat them! They had to drag them down into their holes to save for some future dinner. They took so many branches off of so many plants that 20 gophers couldn't have eaten that amount of food in an entire winter. But heck, the food was just sitting there free for the taking, so like any self-respecting brainy mammal, they had to take it! So much for human superior neo-cortical intelligence!

In desperation, Cindy finally began to try to find ways to coexist with the gophers by luring them away from the flower beds and off into the far reaches of the yard that we didn't care about. She stuffed carrots into the gopher holes in those nether parts of the yard, hoping to give them the message that this was an OK part of the yard for them to live in. It worked! A gopher found the carrots and moved into that part of the yard that very day! Go Cindy! But did that keep them from coming back to the flower beds? Nope! That very same night, that very same gopher came back to the flower beds and used all its extra energy from the nourishing carrots to swipe even more and bigger branches from the hibiscus and roses! Charlie and the gopher thought it was hilarious. Even the loyal dogs looked like they were trying hard not to snicker a little at poor Mom.

Dryer Sheets! Our Gopher Repellent!
In the end, one simple trick finally worked. Dryer sheets. Dryer sheets! Yes, the kind of dryer sheets you stick in your clothes dryer when you do your laundry! After spending a fortune on every possible gopher bait, trap, filler, and gadget, one small box of dryer sheets for $1.49 did the trick. We read at the very bottom of a very long gardening forum that it is an old rancher's trick to stuff dryer sheets into every gopher hole on a large property to drive the gophers away. So we did just that - we went around stuffing dryer sheets in all the gopher holes in all the places we wanted to keep gophers out of. Then we watched. Nothing happened! No new damage. No new devastation! The only new gopher holes that appeared were way out in the nether reaches of the yard! We haven't had a gopher get into our flower beds since! Triumph at last for only $1.49!

We have no idea if dryer sheets will work for everyone else, but if you do try them, please let us know if they work! For now we're just grateful that our own personal plants are safe, and that we didn't even have to kill the gophers. Coexistence is feeling very sweet!

Seedling of the Month...

'White Hot'

Exotic Hibiscus 'White Hot'
'White Hot' Twins in Hot Weather

Our October Seedling of the Month is 'White Hot.' In summer heat, the 6-8" single flowers are vivid yellow and orange with a large white eye. In the cooler spring and fall weather, the flowers are bright red with smaller yellow markings and the same large white eye. The bush of 'White Hot' is large, vigorous, very lush, and a great bloomer. The parents are 'Saffron' and 'Some Like it Hot.' 'White Hot' combines the markings of both parents in one flower, but has the far superior bush of mother 'Saffron.' If you like either of these parents, you should love this new seedling! Watch for 'White Hot' to be released in January 2013.

Exotic Hibiscus 'White Hot'
'White Hot' in Cooler Weather
Exotic Hibiscus 'White Hot'
Another 'White Hot' in Cooler Weather