Poinsettias can acclimate in temperate areas

By Audrey Post
MS. GROW-IT-ALL®

Q: How can I keep my beautiful poinsettia healthy and around for next Christmas? Can I plant it outside or must I keep it in a pot?

A: Even though they are tropical plants, poinsettias can take a little cold if they are allowed to acclimate to cooler temperatures gradually. They can’t take prolonged freezes. The good news is that most of North Florida and a good chunk of South Georgia have only sporadic, short-lived freezing weather, as do areas along the Gulf Coast and South Atlantic. If you have an area that is a warmer microclimate than the rest of your yard, perhaps in a flower bed next to a south-facing block wall or near the clothes dryer vent, it can provide additional protection because it won’t get as cold during a freeze as the rest of your yard.

Because blooming is triggered by the shortened days of fall and the reduction in light, make sure you don’t plant it where a porch light or street light will illuminate it at night. Also, there are a few things you should do while your poinsettia is still living in a pot that will help ensure its successful transition to the landscape.

First, keep it in a place where it gets bright, indirect light most of the day, making sure to pour off any water that drains through to the saucer to keep it healthy. Once the flowering bracts have faded, cut the them off. After danger of frost has passed, trim the stems back to about six inches and plant the poinsettia in a sunny location. Sprinkle a tablespoon of Epsom salts around the plant. This will make sure it gets enough magnesium and prevent leaf discoloration. As the plant gets larger, it will need a larger dose, but one tablespoon is fine for initial planting. Repeat the Epsom salt application in June or July. Apply a general formula fertilizer such as 10-10-10 monthly from May to September, as well.

Keep it well-watered until it’s established, then water it weekly if it doesn’t rain. Plan on pruning lightly every month once the danger of frost has passed, or else the plant will get leggy; your plant will develop side shoots that will need to be pruned, too, but don’t prune after September so the flowering bracts can start forming.

The red varieties of poinsettia reportedly adapt better to the yard than other colors. If a freeze is predicted, make sure you protect your poinsettia with plenty of mulch.

A little poinsettia trivia to file away: The plant is native to Mexico and was introduced to the U.S. in the early 19th century by the U.S. ambassador to Mexico, Joel Poinsett, for whom the plant is named.

Footnote on camellias, which were the topic of last week’s column: Some camellia sasanqua varieties bloom in late summer and some in fall and early winter, but as a rule, they tend to bloom earlier than camellia japonica varieties.

Camellias add to landscape beauty

By Audrey Post
MS. GROW-IT-ALL®

Q: We just bought a house that has several mature camellias on the property. They’re blooming right now and beautiful, and we’d like to keep them healthy. What do we need to do in terms of fertilizer, pruning, etc.?

A: Camellia japonica is a beautiful evergreen shrub that blooms from late fall through winter.
Camellia sasanqua, which blooms in late summer, and Camellia reticulate are less common. Camellias are generally found in USDA Zones 7 through 9, but they do not do well in the extreme heat of South Florida.

There are different varieties, including several dwarf varieties, so it’s easy to find the right camellia for just about any location.

Camellias prefer slight acid soil, 5.0-5.5 pH, but they will do fine in soil with a pH up to 6.5. Since yours are blooming now, your pH must be acceptable. They also need good drainage and air circulation and light shade or high shade, such as the shade provided by tall pine trees.

Fertilize three times a year with one-half pound of fertilizer for each 100 square feet, using a 16-4-8 or 15-5-15 formula. There are commercial blends formulated for camellias and azaleas, but make sure the middle number, which indicates the relative amount of phosphorous, is low. (The first number shows the relative amount of nitrogen and the third the relative amount of potassium.) Our soil is naturally high in phosphorous and any that’s added won’t be absorbed and instead will run off and contribute to pollution in lakes and streams.

The best times to fertilize are March, June and September. Don’t fertilize after September, because it will encourage new growth just in time for early frosts to damage it.

Camellias that have been planted in a good location with room to grow should not need pruning. However, if you inherit one that was not properly sited and needs pruning, do it in March. Remove entire branches instead of shearing the shrub. Shearing not only makes the plant look ugly but also encourages a flush of top growth, which blocks sunlight from the branches in the shrub’s interior. The leaves fall from those branches and you have a bunch of sticks with a mop of leaves on top.

Although camellias don’t like wet feet, they do drink heavily. Water during dry periods every 10 to 14 days until the soil is wet about 15 inches deep. You can use a wooden yardstick to test the soil moisture. A soaker hose or micro-irrigation system is better than an overhead sprinkler to apply the right amount of water to the root zone.

The main pests are scale, an insect with armor that must be attacked when young, and aphids. Frequent inspection and spraying with a horticultural oil, making sure to get the under-sides of leaves as well as the tops, will control pest populations. Make sure to read the label of any product you use and follow directions.

Another perspective on the oleander caterpillar

By Audrey Post
MS. GROW-IT-ALL®

Geoff Newland, a recent transplant from Pompano Beach, Fla., to Bainbridge, Ga., wrote to share additional information about the oleander caterpillar, which was the topic of a recent column. As the owner of a pest-control business for 28 years, he gained a wealth of knowledge that he’s willing to share. Although most literature says the spines of the oleander caterpillar are harmless, the same literature says it feeds only on oleanders -- which we know is no longer true. It’s a cautionary tale for all us gardeners: There are exceptions to every rule, and things can change.

Here's Geoff's message: “As you know, oleander bushes thrive in great numbers in South Florida, and, in season, the oleander caterpillars are everywhere. A customer of mine and her husband were dealing with an infestation of these critters, and she put her bare arm around her husband’s shoulder, where an oleander caterpillar had found its way. She was severely poisoned and spent time in intensive care, and, at the end of it all sustained a permanent scar in the shape of the oleander caterpillar on her arm.

“The real danger from these highly toxic pests (they actually thrive on poison in the oleander bushes) is the two rows of spines on their backs. To touch those is to become really ill! In Florida, at least, gardening with gloves is a must.”

Other critters that can inflict pain, he said, are scorpions and puss moths, which look like slugs covered in hair and have kick like a mule.

One can easily spot the oleander moth cocoons around a home, Geoff said: they pupate under the roof eaves, door and window frames and are easy to spot, so you can sweep them down and bag them up for disposal.

Thanks, Geoff.

Q: My azaleas are looking a bit ragged and ratty, with some branches much longer than the others. Can I prune them now?

A: You can prune now -- if you don’t mind forgoing the spring display of blooms. Pruning now would mean cutting off the flower buds, which began forming in summer. The best time to prune azaleas is after they bloom in spring but before the Fourth of July.

That said, if a neat appearance now is more important to you than having an explosion of azalea color in March, go ahead and prune them. For adult plants, follow each leader branch back to its base, where it branches off another stem, and cut it there. You don’t want to shear an azalea like a boxwood or privet hedge.

For newly planted young azaleas, prune back at least one-third each year for the first two or three years to encourage it to grow bushy and full.

This goes for the Encore azaleas, too, which repeat bloom throughout the year. Pruning them in spring gives the plant a chance to grow more flower buds during peak growing season.

Florida betony a tenacious weed

By Audrey Post
MS. GROW-IT-ALL®

Q: I have a healthy growth of Florida betony in part of my lawn. It is growing in about a 20-foot by 30-foot isolated area. I wish to eliminate it, before it spreads further. I am willing to kill the grass in that place, if that's what it takes. I am up in years and not really able to remove it by digging out all the roots. Please advise me on the best way to kill it.

A: Stachys floridana, also known as Florida betony and rattlesnake weed, is a perennial weed that flourishes in cool weather and goes dormant in the heat of summer. It is spread by stringy white roots that end in a sectioned tuber that looks somewhat like the rattles on a rattlesnake – hence the nickname. Its flowers form seeds that drop and germinate in any kind of soil, further spreading it.

Bad manners are what give it a bad reputation, because it’s not really an ugly plant. It just tends to show up where it’s not wanted and then take over. To say that Florida betony is tenacious is not giving it enough credit. It ranks right up there with kudzu and smilax in the “difficult to eradicate” department. It usually is introduced into the home landscape hidden among the roots of other plants, particularly sod.

Is there any chance you could grow to love it? It’s sort of pretty, it’s native and it’s relatively maintenance- free, although it does disappear on you in summer. No way, eh?

You said digging it out isn’t really an option for you, although that is the best way to eradicate it. However, you could work on beefing up your grass to choke it out. This isn’t the right time of year to fertilize your lawn, but if you can wait until April when soil warms, that’s one possibility.

Since you’re willing to sacrifice the turfgrass, smothering the betony with mulch is one possibility. Use a weed-whacker to cut the betony to the ground before you apply the mulch; the rhizome will still be underground, but the mulch will deprive it of the opportunity to emerge. Any strays that pop through the mulch can be plucked out if the soil is moist.

If you want it dead, you’re going to have to apply herbicide, probably more than once. The most effective time to spray Florida betony is in October, with a repeat application in February, which coincides with the fall and spring flushes of growth. As cool as it has been this fall, it’s probably too late to apply it now. Wait until early February. A product containing atrazine, which is found in most lawn weed-killer formulas including Hi-Yield Atrazien, has been effective. Don’t use a weed and feed product, because you don’t want to encourage the grass to grow until April, when the soil has warmed.

The University of Georgia has tested various herbicides on Florida betony, and reported good results with Monument, which contains trifloxysulfuron; Manor, which contains metsulfuron; and Revolver, which contains foramsulfuron. Timing was key to the effectiveness of each product. As with any herbicide, follow the directions on the label.

Herbicides containing glyphosate, such as Roundup, weaken Florida betony but you’ll have to make multiple applications to kill it. You could start with Roundup now, but it will kill everything. Do you really want a 20- by-30-foot bare spot in your lawn?

Thirsty hydrangea needs repotting

By Audrey Post
MS. GROW-IT-ALL®

Q: I bought a beautiful hydrangea recently that is acting like it wants water, but I’m giving it plenty of water. It’s still in its pot and the roots are pretty tightly wound around the base. What can I do?

A: It sounds like your hydrangea is root-bound, so the water you’re giving it is running right through the pot and the plant is not absorbing any of it. The best thing to do is plant it as soon as possible, but you’ll need to do some work on the root ball to help it survive.

Hydrangeas need morning sun and afternoon shade, or continuous high filtered shade, and moist but well-drained soil. Dig a planting hole the same depth the plant sits in the pot and about three times wider. Take the hydrangea out of its pot and lay it on its side. With a sharp blade – a pruning saw or a machete works well for this task – make deep cuts top to bottom through the root ball about every three inches. Use your fingers to pull out the roots you’ve freed.

Plant the hydrangea, re-fill the soil in the planting hole and make a little berm of soil all the way around it to act as a basin. Water it well and keep it uniformly moist. You should see new growth in a few weeks.

Q: Is it too late to dig caladiums for winter?

A: Can you still find them? Caladiums are tropical and die back to the ground in a hard freeze, which we’ve already experienced this fall here in North Florida. Once the colorful foliage is gone, it’s hard to find caladiums in your flower bed without digging around.

If you want to go to the trouble of digging your caladiums, assuming you can locate them, go ahead. Make sure you wipe off the dirt and store them in clean sand or straw. If you don’t have easy access to either straw or sand, buy a bucket of cheap cat litter. The clean litter makes a good storage medium and the bucket is a dandy storage container.

Don’t wash your bulbs, because storing wet or damp bulbs can lead to rot. Replant them next spring in rich, well-drained soil that has been amended with lots of organic matter, in a location with filtered shade. Too much sun and the colors bleach out; too much shade and the plants get leggy and weak.

Or, you could leave the caladiums where they’re sleeping and see how they perform next year. The first year is always the best one, and the performance tends to diminish a bit each year afterward. I don’t dig my caladiums; I simply plant a few more each spring to keep the show going.