Plants help us celebrate the holidays. Find out if a live Christmas tree is right for you, learn about the development of new poinsettias, and how to add color to your winter garden. We’ll also find out how to keep a bit of summer inside by growing citrus trees indoors and how to succeed with native plants.
You’re listening to Getting Dirty with Master Gardeners. This program is created by NC State Extension Master Gardeners Volunteers. I’m your host, Harold Johnson, and I’m a Master Gardener in Durham County.
Artificial, cut, or live Christmas trees? Which tree is right for you?
Caring for a live Christmas tree
In recent years, more and more people have been selecting live Christmas trees for their holiday decorations. A live Christmas tree can be a wonderful, sustainable choice if you follow a few guidelines:
First, give some thought to the best species of tree for your area. You’ll want a tree that will grow well in your landscape without excessive tending. In North Carolina, Fraser firs are popular choices for cut trees, but they won’t grow well in the Piedmont or Coastal Plain. In our area, choose Leyland cypress, Arizona cypress, Virginia pine or eastern red cedar. These species tolerate a wider variety of sites, soils, and climates. They will, however, require a bit more pruning work on your part to maintain a Christmas-tree shape.
Next, think about the size of the tree you need. A big tree gives instant impact in the landscape, but it will also suffer more transplant shock and will need much more attention in its first two years than a small, tabletop-sized tree. The American Landscape and Nursery Association suggests that a 5 foot pyramidal conifer should have a 2-foot diameter root ball to survive transplanting. Smaller root balls prevent the tree from taking up adequate moisture to support its crown. If you’re considering a live tree to transplant into your landscape, it pays to go small.
Third, don’t let the root ball dry out. It’s got to stay moist to keep it alive. A cut tree can take up as much as a gallon of water on its first day and multiple quarts of water a day after that. But unlike a cut tree, you don’t want to keep a live tree in deep standing water. You need to think of it as a huge house plant. And that house plant is going to be really, really thirsty in your centrally heated home. Keep no more than an inch or two of water in a deep tub for your live tree—any more and your tree will drown.
It will help to mist the branches with water, but that may not work with your tree decoration scheme, particularly if you plan to light the tree. A better idea is to put the root ball in a tub filled with moist sawdust or leaves. Check the soil several times a day, and if it feels at all dry, water it. Your days this season may be busy, so buy yourself a little extra time between waterings and cover the root ball in crushed ice. It will slowly melt into the root ball and keep it moist for longer. But it’s going to need regular attention. Don’t be surprised if your full-size live tree needs a gallon of water a day.
Large, hot lights will dry out the tree, so choose light strands with smaller bulbs that don’t give off much heat, or light the tree indirectly.
And as with a cut tree, keep it away from both heating ducts and drafts. A cool spot is ideal. You can slow down the drying process by lowering your thermostat a few degrees. Put on an extra sweater and remember—Christmas time is supposed to be cold!
Finally, don’t keep the tree inside your house for very long—a week to ten days at the most. Long exposure to indoor temperatures can trick trees into thinking their winter dormancy is over. Then, if the trees are set outside into severe cold after the holidays are over, they’ll develop winter injury like foliage burn and bud death. The sooner you replant your live Christmas tree, the better its chance of survival.
When it’s time to plant the tree outside, be gentle. Take a few days to acclimate your tree to outdoor temperatures by putting it in a sheltered space outdoors. The space should be uninsulated but out of the wind. A carport or shed is ideal. Don’t forget to keep the tree watered during this transition time.
When you select your planting site, keep in mind the tree’s mature size. Do you have a dwarf variety, or will your cypress tree get to be 40 feet tall? Make sure your tree will get enough sunlight in its new spot to thrive, and that it won’t grow up through power lines or into the canopies of other trees.
To plant, dig a planting hole the same diameter and slightly shallower than the root ball or container size. It’s better to plant shallowly than too deep, because the root ball will settle over time. Remove any burlap, nylon, wires, or plastic from the root ball. Break up or divide any coiled or massed roots on the outside of the root system and shake off excess soil to discover if any of the internal, woodier roots are coiled or damaged. If they are, remove them. Level the surrounding soil with the top of the roots, and fill in with the native soil. After planting, spread two to three inches of mulch over the planting area. More mulch is not better. Deep mulches can provide shelter for voles, who will nibble the trunk with impunity.
Use guy wires for the first year to keep the tree in place until its root system develops. Don’t attach wires directly to the tree; instead, wrap a rubber hose or rags around the trunk where the wires will be attached.
Water the tree after planting, but wait to fertilize it until spring after the tree has started to grow. Do not over fertilize in the first year, especially with nitrogen, until roots have had a chance to become well established.
It’s a lot of work to keep a live Christmas tree going, but it can be worth it. Each year afterward, as you come and go and pass by the tree in your landscape, you’ll remember the special holiday when you planted it.
Carol McPherson introduces us to the perfect tree —the American Hornbeam. Maybe you grew up calling it Blue Beech,Musclewood, Ironwood, or Water Beech tree. Find out if this tree is perfect for you too?
Hello, I’m Carol McPherson and this is Tree Talk. I’m a NC State Extension Master Gardener Volunteer from Orange County and today I’m going to talk about what I call the perfect tree. Yes, there really is one and it’s growing right next to my driveway. I wish I could say that I planted it, but it was there when we bought our house five years ago. If I’m really truthful, I will have to confess that: first, I mis-identified it, and secondly, when I found out its true identity, I’d never heard of it.
It looked very much like a beech tree. The trunk was smooth and gray, and the leaves were roughly the correct size with serrated edges that some years stayed on the tree all winter. I grabbed my trusted Trees of Carolina Field Guide by Stan Tiekela, and found it– he called it a Blue Beech. It had clearly been planted as a specimen tree in a nice border between our house and the one next door, where it was thriving and maintained its beautiful shape without pruning or any care whatsoever. After some time I finally noticed that the leaf edges were not wavy like a true beech tree’s, and that they were doubly serrate—too different, even to my uninitiated eyes, to be a cultivar of beech. This time I read the field guide closer. Yes, it was called a Blue Beech, but its scientific name was carpinus caroliniana, a member of the birch family. I know now that it’s more accurately named: the American Hornbeam. To add to the confusion, it’s also called Ironwood and Musclewood as well as Blue Beech.
There are about 25 species of Carpinus, but the American hornbeam is the only one native to North America. It grows from Minnesota east to Maine, and south to eastern Texas and northern Florida. Carpinus is the classical Latin name for the Hornbeam, and comes from the word, “carpentum”, a Roman horse-drawn vehicle with hard-wood wheels. The wood of the hornbeam is heavy and hard. It is so hard that it was the traditional stuff of axles and cartwheel spokes before iron became cheap enough to take over. It’s still used for tool handles, longbows, walking sticks, walking canes and golf clubs. One writer said that his favorite brewery, powered by a 19th c. steam engine, has hornbeam cogs that are better than iron because they don’t shear.
It’s a smallish tree, growing about 30 feet tall at maturity, with a spread of 25 feet. It has a relatively low canopy with a typical clearance of 4 feet from the ground. It grows at a slow rate, and under ideal conditions can be expected to live for 80 years or more. My hornbeam is single-trunked and does not sucker, but you will more commonly find it growing in the forests or along river bottoms, with multiple stems, and often leaning out of the shadier parts of the woods, reaching for the sun.
Its most distinguishing feature is its bark. It is smooth and gray like the beech tree’s, but is lined with smooth, rounded longitudinal ridges that look just like muscles—hence its other common name, Musclewood. Hornbeam looks taut and buff, as if it goes to the forest gym twice a day and lifts … iron. Hence its other common name: Musclewood. Once you identify this feature, you will not mistake it for any other tree.
The leaves of the hornbeam are alternate, simple, and 3-5 inches long. They are dark green on top, almost glossy, and lighter green with soft hairs on the under side. The leaf edges are sharply and doubly serrate. In the fall, the leaves often turn respectable shades of yellow, orange and red. Flowers appear in spring in separate male and female catkins, with the female catkins giving way to distinctive clusters of winged nutlets. The nutlets are contained in a papery green bract, 2-4 inches long, that hang in clusters from the tree. These nutlets are eaten by a number of songbirds, ruffed grouse, ring-necked pheasants, bobwhite, turkey, fox, and gray squirrels.. White-tailed Deer and Eastern Cottontails munch on leaves and twigs, and Beaver eat the bark. Red-spotted Purple and Eastern Tiger Swallowtail butterflies use hornbeam as a host plant.
So why do I say that is a perfect tree? Partly because it is SO attractive with its rounded form, its interesting silvery blue muscular bark, its excellent blend of fall colors, and its curious hop-like fruit. In winter, the bark of the American hornbeam and the nutlets that cling to the treeadd an interesting dimension to the landscape.
I also place this tree in the perfection category because it has virtually no significant negative attributes. There are no serious insect or disease problems. Got an open, sunny spot in your yard? Got thick shade? This tree performs well in both full sun and full shade. Got an area that seldom gets watered, or maybe a boggy spot with poor drainage? No problem—it’s an amazingly adaptable tree, tolerating both dry conditions and even some standing water. It’s not particular as to soil type or pH—either acid or alkaline will work just fine. It is somewhat tolerant of urban pollution. Unbelievably, it is even tolerant of black walnut toxicity and can grown in the shadow of these trees. The only setting it dislikes is a place where it is exposed to salt spray, so if you live on an ocean beach, you may want to find another candidate.
This is simply a handsome tree in any location, and will grow slowly and politely until it reaches a height and spread of 20 to 30 feet. It will grow with an attractive open habit in total shade, but be dense in full sun. It has the advantages of being a native tree, beautiful to the human eye, and a source of food and shelter to wildlife. So call it by any of its names: blue beech, musclewood, or ironwood, I believe the American Hornbeam is underused and deserves a closer look. It’s best planted in late winter or early spring in a balled and burlapped state, and hopefully it will make you happy for years to come. Michael Dirr, the guru of trees and woody plants, asks: “Is there such a thing as a lousy carpinus? Does not appear so.”
This is Carol McPherson and you’ve been listening to Tree Talk.
Poinsettias have started showing up…everywhere. NC State plays a big role in bringing new cultivars to the marketplace and you can see what’s new at the JC Raulston Arboretum Poinsettia Open House on December 6th. Find out more as Lise Jenkins talks with Dr. John Dole, department head for horticultural science at NC State and a poinsettia researcher.
It seems like they show up earlier each year. There’s this lull between Halloween and Thanksgiving and then bam —they’re everywhere. Wrapped in cellophane pots of green and gold —those Christmas Poinsettias. My first reaction is always terror —all the things I haven’t done. But their jolly red faces with yellow smiles win me over and I get in the holiday sprit. Recently, I visited the JC Raulston Arboretum and learned that North Carolina plays a big part in spreading that Christmas cheer.
My name is John Dole, I am the department head for horticultural science. My other life I am a horticultural researcher and teacher and one of the projects I work on is poinsettias.
Last year 4.3 million pots of poinsettias were produced in our state and they had a wholesale value of over $17 million dollars.
Its big business. Its one of our most important potted flowering plants. It has such a long sales season. pretty much right after Thanksgiving to right up to Christmas. People are buying and giving poinsettias away. Of course, their used a lot for decorations in office buildings, malls. Starting to see them out already, So yes.
I’m standing in one of three greenhouses overflowing with over 1000 poinsettias. I had no idea they could range in colors from snow white, blood red, to hot pink. The bracts —the colored leaves of the plant, can be smooth like spears, or pointy like oak leaves. They can be tiny with short steams or big and floppy.
Oh, well the first bench right here is really great. Well you can’t see it, but we have a lot of colors right here and that’s the first thing people notice right off. Lots of colors. The original Poinsettia which is native to Mexico, is a tall perennial shrub and it has red bracts. Of course we are mostly familiar with red, that is the color that is Christmas.
These plants are in the greenhouse for the annual poinsettia trials conducted by NC State University. Each year, new plants are introduced into the market. Deciding which new variety to grow can be a risky decision and a big investment for North Carolina growers. So the horticulture department conducts trials evaluating the color, bract shape, foliage, and performance of over a hundred cultivars each year. Then they open up the greenhouses at the Raulston Arboretum to industry breeders, growers, and vendors to come and see the results for themselves. Dr. Dole pointed out some things the pros look for.
So within the red poinsettias what we look for is if you look at the shape of the bracts some are very rounded with no points on them, just a kind of long elongated bract. Some of them look like oak leaves and the oak leaves are more like the original poinsettias in Mexico. That has just a different look. Some people like it, some people don’t, and the growers in the industry are always trying to second guess what it is people want. That’s the combination of agriculture and fashion.
Fashion seems to be a big driver in this business and breeders are always looking for the next big thing that might capture shoppers’ attention. Dr. Dole explained that while they may look so different, poinsettias are just one species. Breeders started to change that by developing hybrid plants that produce amazing results.
But a few years back the breeders were able to incorporate a second species into poinsettias which has produced these spectacular pinks. If you look at them you can see some other differences also. The bracts are smaller, they’re more elongated, there are some that are white, some that are pale pink, they just have a really different look. They just look more like a true flower. So that’s probably been the biggest advance in the last few years has been the release of these hybrids. Some of them are just so speculator.
Breeders hope that all these different colors might expand the market for poinsettias.
That’s one of the hopes, because these gorgeous, gorgeous pinks are beautiful, but we don’t think of pink as Christmas color. So their market acceptance has been limited around Christmas. We did some work with the “Love You” pink, which is one of the hybrids for October. Getting it to flower for breast cancer awareness, just gorgeous plants, and they came out well. Well also the spring holidays, the light pink is what we might think of more as Valentines Day. So theres a chance that the poinsettias type might become more broadly distributed across the season.
I was drawn to a fabulous hot pink plant. It was the perfect shape, its bracts were outlined in white so you could appreciate each leaf, and the plant had dark green foliage. I started envisioning ways to get my hands it for Mother’s Day. I just have to keep it alive until then.
They’re a good indoor plant they last a long time, there’s no reason, other than the fact that we so strongly associate them with Christmas, that we should not be buying them for other holidays because they do last a long time.
The appearance of any plant has a lot to do with its environment. When the poinsettia trials are opened to industry the plants are displayed in a variety of settings. But then Dr. Dole takes it a step further and continues his research at home.
Part of our open house is we put poinsettias in to our post harvest building. In that we have florescent lights cause the color of red, and pink in particular, and well white for that matter. It changes depending on what light its under. In the greenhouse we have lots of natural sunlight which all the colors look good under. But when you bring them indoors the quality of the light makes the colors look very different. And so, that’s part of our open house is the growers will come in and see how they look inside. The light inside my home is a little different still so, it has more warmer tones and so I like to see how they look there. To see how they last. And I like poinsettias. I did my PhD on them and I worked for a professor when I was an undergrad and I helped him on his poinsettia work and they are a fascinating plant. They have a lot of botanical quirks that we don’t find in any other plant. So they’re just a real cool plant so I like them. So yes, I will be brining lots of poinsettias home
NC State researchers are looking for more than just a pretty plant.
In addition to the cultivar trials we do other research on them because we have all of these different cultivars coming in and we take, especially the more important ones, and we’ll do other work on them. We may look for different ways of growing them, ways to grow them faster, cheaper easier. We sometimes will do various pest control methods. The big experiement we have this year is going to be on post harvest. We are taking a broad range of the cultivars and then we are going to see how long they last. They in general last a very long time but there is some variation. And we’re trying to look to see. You asked the question of what should the consumer do with them. Well the question is also out there as to how the retailers should sell them. So that’s what we are going to be looking at. Under what conditions should the poinsettias be sold and if they can’t provide just the right conditions how much life can they expect. If they can’t give them enough light, then what happens, if they give them too cold of temps then what happens? That sort of thing. So we’ll be trying to generate info that the retailers can use when they sell and distribute the poinsettias.
Dr. Dole had done his PhD work on poinsettias. I realized this was my chance to get expert advice on how to keep them alive through the holidays.
They’re very simple, they’re one of our more durable plant in the sense of if you give them a good location they will last a long time. Generally what you want is a nice bright location, you want them out of direct sun, and you want it in a cool, but not cold room. Poinsettias are a tropical plant so they get kind of cranky below 60 degrees. Now luckily people tend to get kind of cranky below 60 degrees so they are actually very well matched to what we live in. So if you’re one of those who keeps your house on the cool side, then if you have a nice bright location, chances are your poinsettias will last a long time until finally you get tired of them and throw them away.
How do I select a healthy plant?
You want to look for, you check the bracts out. Make sure they’re nice and fresh. Look for any discolorations on the bracts, you don’t want to see that. Check the leaves out, you want to make sure the leaves are nice green. You aren’t starting to see any of the yellow leaves down below. Which indicates the plant might be starting to get a bit old. If you look at the center of the plant you will see the little round flower buds. Which you want to do on some of the flower buds, you’ll start to see some of the stamens starting to come out the little fuzzy parts. And what you want to do, you want a few stamens but you don’t want all the flowers to be showing lots of stamens. Sometimes if they are very old you’ll start to see the seed pods coming out. You want to get a plant that’s younger than that so it will last a bit longer. In general that should do it. As you’re bringing it home, they are a tropical plant. So cold weather, if you are going to be doing a lot of shopping you know and the temp is at freezing or close to freezing then you are going to want to be sure to get your poinsettias in the last part of the day or get them and bring them home. Get them and bring them home. Don’t let them sit in a cold car. Because that will cause the lower leaves to fall off. If its really cold you will get brown patches on the bracts. Which is known as chilling damage. On the other hand, occasionally we are blessed with these wonderfully warm days in Dec. North Carolina is a great place for weather. And the car can get really hot in which case they can overheat. In which case you need to crack the windows so it doesn’t get too hot. So they are living organisms so yeah, we don’t want to let them sit in a cold, cold car or hot car.
I asked Dr. Dole if plant breeders had reached the limits of ways they could change poinsettias.
It just surprises me that after all these years and as much plant exploration has gone on, as much plant breeding that’s going on, there are still new things that surprise me and excite me. You know, when these poinsettia hybrids came out it was just wow, those are different and stunning. Pack trails, spring, takes place in California, that’s where the industry releases its new material. Even though I’ve been going for many years every year I always find something that I just didn’t expect. You know the creativity of growers and breeders in the industry is just a lot of fun. So I think its every year something catches me off guard. In a good way.
At the conclusion of the trails, the JC Raulston Arboretum has an open house for the public where you can go and check out what could be coming to a garden center near you. Check our website, gettingdirtyradioshow.org for their schedule. I’m Lise Jenkins and I’m a Durham County Extension Master Gardener Volunteer.
Your winter garden doesn’t have to be a drag and colorless place. Charles Murphy brings us ideas for adding color to your garden year round.
Growing citrus indoors keeps a bit of summer in your site year round. Amy Hill brings us sustainable strategies for successfully growing citrus indoors year round.
We’re heading into the darkest, coldest days of the year, but if your holiday plans don’t include a trip to the Caribbean, you can still enjoy a sense of the tropics in your own home this winter. All you need are a few potted citrus plants.
Many citrus trees are naturally dwarfing, meaning that even when grown in the ground they do not get much larger than 8-12 feet tall. This shorter stature makes them excellent candidates for container culture, and most varieties do not require pollination to set fruit. Just follow a few critical cultural tips to get them off to a good start:
Choose the right container. A 12-inch diameter pot is an appropriate size for a 2- to 3-year old tree (3-year-old trees should begin to bear fruit). Plan to repot every year or two as the tree grows. Don’t start with an oversized pot, though, as doing so makes assessing moisture levels difficult. Whether you use clay, plastic, or fiberglass pots, ensure they have sufficient drainage holes. Don’t hesitate to drill more using a drill bit suited for your container’s material.
Don’t add gravel to the bottom of the pot, as research shows this practice worsens drainage over time. Instead, use a soil-based potting mix with a 1:3 proportion of perlite or bark to soil. If your potting soil is heavier, you can add more perlite until it reaches a 1:3 ratio, or you can add 1” cedar shavings intended for small animal bedding. Mix the amendment so it’s well distributed throughout the container. Avoid using any potting mix with water-retaining granules or wetting agents, which can keep the tree too wet for too long.
Citrus trees need to have sufficient moisture but should never be waterlogged. Your watering frequency will be directly related to the porosity of your soil and the dryness of your home’s air. Elevate the pot above any saucer so it never stands in water. When the surface soil dries out, use your finger, a pencil-sized wooden dowel, or an inexpensive soil moisture meter to check the subsurface moisture levels. Only water if the soil at the root level is dry. Deep watering once or twice a week will be healthier for your plant than frequent shallow waterings.
When transplanting into a new container, make sure the root flare is visible above the soil line. The fibrous root mass should lie just under the soil’s surface. Keep soil and mulch off the trunk so as to prevent rot. Water deeply to settle any air pockets.
Fertilize your container-grown plant with a slow-release fertilizer designed for citrus, or one with at least a 2-1-1 ratio of nitrogen to phosphorus and potassium. Check the label to ensure the fertilizer contains trace minerals like iron, copper, manganese, and boron, as citrus plants can suffer from micronutrient depletion. Supplemental or foliar feeding with kelp or fish emulsion can be beneficial, unless the aroma attracts your house pets to dig in the container.
Give indoor citrus as much sunlight as possible. Eight hours of sunlight from a south- or southwest-facing window is best; if you can’t provide more than 6, supplement with grow lights. Let them spend the summers outdoors, but transition them to indoor conditions before freezing temperatures are forecast.
Indoor-grown potted citrus can be susceptible to aphids, scales, and spider mites. Look on the undersides of the leaves for these pests and if you find them, wipe them off with a wet cloth or a spray solution of mild dish soap and water. Particularly bad infestations can be controlled with horticultural oil measured to label instructions.
‘Improved Meyer Lemon’ and Kaffir limes are among the best suited varieties for indoor culture, and both are fairly easy to find at garden centers. Kaffir limes have wrinkled skin and are frequently used in Asian cooking. The blooms of both plants will fill your home with gorgeous aromas.
I sat down with Chatham county horticulture agent, Charlotte Glenn, about why we should consider using native plants in our gardens.
Not included in this transcript.
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