Vegetative plant propagation is a way for one plant to create another plant without the need for pollination to occur. This process is often much faster in achieving a new plant than growing from seed. The genetics of the parent plant can be carried on through this vegetative propagation method. There are many methods to propagate plants and the one covered in this article was taught to me by my grandmother many years ago – layering. Layering is a science and an art and has been performed by humans for over four thousand years.
Propagating plants by layering can be accomplished in several ways, including simple, tip, air, mound, compound, and runner production layering methods. Many plants in nature propagate by layering accidentally when long, low-lying limbs contact the soil around the plant and are eventually covered by leaves from other surrounding trees and shrubs. This creates an organic cover over a part of the limb and keeps the area moist. This creates the situation for adventitious roots to develop at the soil contact area. This occurrence is called simple layering and is often mimicked by gardeners in the landscape. Not all plants respond to this type of propagation, but several common species that do are azaleas, jasmine, viburnum, climbing rose, and grapevines.
Unlike simple layering, tip layering involves digging out a shallow 3–4″ hole, which will allow space to bend the end of the branch down into the hole with the tip out the other side. Then, simply cover the hole to keep the branch in the ground. It may take something with a little weight placed over the covered hole to keep the branch from popping out. A brick or rock may be all that is needed. Both methods will take months for enough roots to develop before clipping the branch with a new plant ready to be dug and set somewhere new. For best results with both simple and tip layering, begin either in early spring with last seasons growth or late summer, utilizing that current year’s growth.
Air layering is a fun adventure to rooting a new plant and can be used with both outdoor and indoor plants. It can be used on outdoor plants like camellia, azalea, maples, and magnolia, or indoor plants including weeping fig, rubber tree, and dieffenbachia. This type of layering requires a bit more planning and preparation than simple or tip layering. If the plant has a bark layer surrounding the cambium layer (this is the growing part of the limb and trunk and appears green) this area will need to be removed with a sharp clean knife. Choose a 1- ½ inch long area of the limb and scrape this area to remove the cambium layer located just beneath the bark. This is done to prevent the outside limb area from reconnecting back to the limb portion connected to the plant. Sphagnum moss will be needed to wrap around the wound site to create a rooting zone. Be sure to soak the moss with water by immersing it in a bucket of water, then squeeze it out. Wrap the moss with plastic wrap, making sure the moss is fully covered and tucked inside of the plastic. Both ends of the plastic wrap need to be secured tightly with twist ties or string. Make sure it remains tight throughout the 2 – 4 months needed for rooting to occur. If this process takes place in a sunny location, cover the plastic wrap with tin foil to block out the light.
There are other methods to layering plants and if you are interested, search online through the University of Florida IFAS EDIS site or contact your local UF IFAS Extension office in your local county. Enjoy growing your new plants.
We grow many types of hydrangeas in North Florida. In order to prune your hydrangeas at the correct time of year, you need to identify which types you have in your garden.
Bigleaf hydrangea (Hydrangea macrophylla) Bigleaf hydrangea (Hydrangea macrophylla) comes in mophead and lacecap flower forms. They bloom on old wood, so prune in summer after blooming is finished. Repeat bloomers, such as ‘Endless Summer’ bloom on both old wood from the previous year and on the current season’s wood. You can prune after the first bloom and still get a bloom later in the season.
Oakleaf hydrangea (Hydrangea quercifolia) A native hydrangea that blooms on old wood, so prune after flowering. This type requires little pruning, only to maintain size and shape.
Panicle hydrangea (Hydrangea paniculata) These shrubs bloom on new wood, so prune in winter or early spring before new growth emerges. ‘Limelight’ and ‘Pee Gee’, are examples of this type. Plants only require pruning to shape or thin out the shrub.
Here are some additional pruning tips for your hydrangeas.
For all types, check for winter-damaged wood in early spring. Remove all dead branches before buds start to open. Some plants need rejuvenation pruning. Old wood may die back or be less productive, so in early spring remove very old stems at the base. This stimulates new growth. Deadheading flowers (cutting off spent blooms at a set of leaves) can happen as needed.
It’s always fun to add new plant to the landscape. And it’s even more fun to propagate your own plant material. The question is, what plant propagation method is best? The answer depends on a number of factors such as:
How much time and money is available?
Is a uniform crop desired or is trait variation preferred?
What is the plant species being propagated?
Plants can be propagated either by seed (sexual propagation) or by segments of vegetative material (asexual propagation). Sexual propagation takes far less time and effort because new plants are being started from the seeds (offspring) of parent plants. This type of propagation promotes genetic diversity because offspring may not have the exact characteristics of the parent plants. Sexual propagation increases the possibility of hybrid vigor, which is the improved quality of plant material to that of parent plants. Asexual propagation usually takes more time, but generally ensures that propagated plants will maintain the same characteristics as the parent plant. For some species it may be the only way to pass on desired traits to subsequent generations and it may be the only way to propagate certain species. A plant produced vegetatively can become larger than a plant produced by see in the same amount of time.
Tips for Successful Sexual Propagation
Seed Collection – Seeds should be collected when fruit is ripe, just before they fall to the ground. In general, seeds should be cleaned, dried, and stored at 40 degrees Fahrenheit (in a refrigerator). However, palm seeds should be planted immediately after harvesting and cleaning.
Seed Dormancy – Some seeds have thick seed coats the inhibit germination. Some seeds need to be scarified (breaking of the seed coat) and/or stratified (stored in a specific environment) in order to germinate.
Seed Sowing – Seeds can be germinated in flats or other suitable containers in a seed starting media. Seeds should be planted at a depth of two to three times their diameter, but no deeper than 3 inches. Cycad seeds should be planted just below the medium surface.
Seeds stored in an envelope. Photo Credit: University of Florida/IFAS
Tips for Successful Asexual Propagation – In general, asexual propagation is the propagation of plant material from cuttings of stems, leaves, and/or roots.
Rooting Hormones – Increase rooting percentage, hasten root initiation, increase the number of roots per cutting, and increase root uniformity. Auxin based rooting hormones (Indolebutyric acid (IBA) and Naphthalenacetic acid (NAA)) are available in dry or liquid forms. It is important to use the correct concentration for the particular plant species because over application can cause damage to cutting base.
Sticking Cuttings – Cuttings should be stuck in the medium only deep enough to support the cuttings and hold them upright (1/2″ to 1″ deep).
Post-Rooting Care – Fertilization should be applied as soon as roots emerge from the cuttings. However, overfetilization can increase soluble salts and burn roots.
Examples of Asexual Propagation
Softwood Cuttings – Taken from woody plants usually three to four weeks after a new flush of growth. Commonly propagated species using this method include: crape myrtle; magnolia; oleander; azalea; jasmine; and boxwood.
Semihardwood Cuttings – Similar to softwood cuttings, but the lower portion of the cutting has become lignified (woody). Usually taken from new shoots six to nine weeks after a flush of growth. Commonly propagated species using this method include: camellia; pittosporum; junipers; and some hollies.
Hardwood Cuttings – Taken from the previous season’s growth, just before or during the dormant period. Commonly propagated species using this method include narrow-leaved evergreens and deciduous species during the dormant season after leaves have dropped.
Leaf Cuttings – Comprised of only the leaf blade or the leaf blade and petiole (leaf stalk). Cuttings are stuck upright in the propagation medium with the basal end (petiole end) of the leaf inserted into the propagation medium. Commonly propagated species using this method include begonias and peperomias.
Root Cuttings – Taken in late winter or early spring from two to three-year-old plant material. Plants propagated by root cuttings may not reproduce true to type if they are budded or grafted. Commonly propagated species using this method include: plumbago; bayberry; oakleaf hydrangea; and yucca.
Plants being propagated by leaf cuttings. Photo Credit: University of Florida/IFAS
My obsession with plants started with the purchase of my first house in Waverly, Alabama in the late 90s. I bought a house with seven acres and of that about 1.5 acres was a fenced yard. The landscape was not very appealing, so I was on a mission to make it beautiful yet functional for my dogs. The only problem was, as a new homeowner, I had very little expendable income for my burgeoning plant habit. This dilemma forced me to be a resourceful gardener.
Shop the discount rack at garden centers
Many retail garden centers (especially mixed use stores with limited plant space) will discount plants simply because they are no longer flowering. Plants look perfectly healthy but are just not considered “retail ready” anymore, so rather than hold them over until they bloom again and appeal to most shoppers the stores tend to mark them down.
Plants are either growing or they are dead, so it is common to find some outgrowing their container and are getting “potbound” which means the root system is outgrowing the pot. Potbound plants are hard to keep watered without wilting and the solutions are to transition to a larger pot or plant in the ground. Most garden centers are not equipped to pot up overgrown plants to larger containers, so the easier solution is to sell them quickly. If you purchase a plant with circling roots be sure to trim the bottom and score (slice) the root ball to encourage roots to spread laterally.
Avoid plants that appear diseased (leaf spots, brown stems, mushy parts, rotting odor) or have active feeding insect activity.
Compliment other gardeners’ plants
When you get gardeners together, they inevitably start swapping plants. I really don’t have an explanation for this other that good old southern hospitality, but I’ve noticed over the years that when you express appreciation of plants to other people they tend to end up in your own yard. Ask if you can take a pinch (for cuttings) or offer to divide a clump of crowded perennials and you are on your way to a trunk full of plant babies.
I can’t recommend this for multiple safety reasons, but I have been known to photographs plants in my travels then strike up a conversation with a homeowner who insisted I take one home.
Experiment with basic propagation techniques
Grow flowers from seed. Either purchase seeds (usually under $2/pack) or collect seed heads from spent flowers in your own garden. After flowers fade, allow them to set seed then either crush and distribute in other parts of your garden or store in a cool, dry place until you can swap with friends.
Division – clumping perennials such as daylilies, cast iron plant, iris or liriope can be dug up and cut into smaller pieces with a shovel or machete. You only need to be sure to have buds on top and roots on the bottom to make a new plant. Other plants create offshoots that can be removed from the parent plant. Examples of these are agave, cycads, and yucca.
Cuttings – the list of plants that can be propagated from stem cuttings is endless but a few that are very easy are crape myrtle, hydrangea, and coleus.
Hydrangea leaf spot disease Photo credit: Larry Williams
It is not uncommon to see leaf spots on your hydrangeas during late summer and fall.
These spots are caused by a number of fungal diseases. Plant fungi and wet weather go hand-in-hand. Florida’s high humidity, heavy dews and frequent rains during spring and summer provide perfect conditions to allow fungal diseases to flourish. Bacterial leaf spots can be part of this foliage disease mix, too.
Common foliage diseases seen on hydrangeas this time of year include Phyllosticta leaf spot, Target leaf spot, Bacterial leaf spot, Botrytis and Cercospora leaf spot.
These foliage diseases are the norm rather than the exception as we move into the wet summer months and on into fall. As a matter of fact, you would be hard-pressed to find any hydrangea in our area without some evidence of infection now.
This late in the year it is more of a “grin and bear it” problem. In other words, it’s too late to do much about the fact that your hydrangea plant has leaves covered in ugly spots. By now many of the infected leaves are turning brown, withering and dropping prematurely from the plant.
Cercospora leaf spot is one of the most common foliage diseases of hydrangeas. Along with most of the leaf spot diseases, it begins as small dark-colored specks on the leaves. The small specks generally go unnoticed. But as the spots continue to slowly enlarge, mostly maintaining a circular shape, they become more obvious. With heavy infection, individual spots can coalesce forming larger irregular shaped brown areas on individual leaves. The individual spots may have a purplish halo with gray center.
There are some fungicides that can help prevent these leaf spots. But you’d have to begin treatment early in spring before any leaf spots exist and spray the plant every 10 to 14 days during favorable disease development (humid, rainy weather), which is pretty much our spring and summer months. These types of diseases are prevented, not cured. That’s the “grin and bear it” part of waiting until now.
The fungus survives on infected leaves. So, the best thing to do now is to remove and dispose of infected leaves. Also, be careful to not wet the leaves when irrigating the plants during the growing season.
New leaves of spring should be spot/disease free as they emerge. But the cycle of life for these leaf spot diseases will again result in spotted/diseased leaves on your hydrangeas next summer and fall without persistent treatment.
The good news is that these leaf spot diseases normally do not cause permanent/long-term damage for hydrangeas. They just make the plant look ugly.
H. macrophylla ‘Bloomstruck’ Photo courtesy of Andrea Schnapp
Generally, when folks find out what I do for a living, among the first questions asked is “What is your favorite plant?” Being somewhat of a plant nerd, that can be a tough question to answer! However, I usually circle back to the same answer, “Hydrangea”. There are many reasons my fellow gardeners and I love hydrangeas. It’s undeniable that few plants conjure more fond memories of summers gone by or cause more impulse purchasing at nurseries than a hydrangea in full, billowy bloom. Additionally, few specimen shrubs give more floral firepower and ask so little of the gardener in return. My own love affair with hydrangea stems from my first propagation experience, a softwood cutting of Hydrangea macrophylla ‘Nikko Blue’ (taken with the help of someone who knew a lot more about what they were doing than I did) that, seemingly magically, sprouted roots in a makeshift greenhouse, a cypress box with an old, crusty, sliding glass door. Hydrangeas hooked me. However, even with all of those attributes to its name, Hydrangea, as a genus, remains underappreciated and underutilized in modern landscapes. Let’s shed some light on the two primary reasons for gardeners’ failure and frustration with hydrangeas in the landscape and highlight some of the best Hydrangea species and cultivars to look for at the nursery!
First, hydrangea has a reputation as being a high water user. As the name (hydrangea comes from “hydor”, which is Greek for water) might suggest, hydrangeas are indeed water sensitive. However, this does not necessarily mean they require more or less water than other plants, rather they simply betray drought quicker than most other plants. This feature makes hydrangea particularly useful in the landscape as an indicator plant. As a general rule, hydrangeas (particularly those planted in too much sun) wilt in the afternoon heat; this is totally normal. However, if the plants remain wilted the next morning, it is an indicator to the gardener that irrigation is required! If they don’t get irrigation soon after telling you they need it, the plants may begin to decline. Rather than being viewed as a drawback, think of this feature as an early warning system. Name another plant that looks out for us gardeners like that!
The second primary reason people fail with hydrandea is improper site selection. Attempting to grow hydrangea in full sun in Florida leads to less than spectacular results. All species of hydrangeas are most happy when sited to receive at least some afternoon shade, if not filtered shade throughout the entire day. Exposure to blistering afternoon sun is problematic and results in increased wilting from heat stress, increased irrigation requirements and “bleached” flower coloration. Remember, there are fewer frustrating things than growing the right plant in the wrong place!
Now that you know how not to fail with hydrangeas, it’s time to select the proper plant for your property! Three primary species perform noticeably better here than the rest of their kin and deserve the gardener’s consideration in Northwest Florida: H. macrophylla (Bigleaf Hydrangea), H. quercifolia (Oakleaf Hydrangea), and H. paniculata (Panicle Hydrangea).
H. macrophylla, the old-fashioned hydrangea everyone’s grandmother grew, is truly one of the standouts in the shady, Southern landscape and commands attention when in flower. Sporting giant “mopheads” of inflorescences in gorgeous hues of blue (or pink, depending on soil pH), H. macrophylla is an extremely low maintenance plant, requiring only periodic irrigation and infrequent fertilizer; H. macrophylla even tolerates salt spray and can be grown on the Gulf Coast! By far, the greatest percentage of questions I receive concerning H. macrophylla involve plants not flowering because of pruning at the wrong time of year. For best flowering results, time pruning of once-blooming traditional cultivars like ‘Nikko Blue’ soon after flowering is finished in late summer. These plants set flower buds on the previous season’s wood; pruning older cultivars in the fall or winter may rejuvenate the plant but will prevent flowering the next year! Fortunately, over the last twenty years, advances in Hydrangea breeding have given gardeners the option of planting remontant cultivars that bloom on current season’s wood. Commonly sold remontant cultivars like ‘Endless Summer’, ‘Penny Mac’, ‘Bloomstruck’, and ‘All Summer Beauty’ have an early summer flower display like the traditional types but then continue to flower periodically throughout the rest of the summer! Even better, they may be pruned at any time without worry of damaging the next season’s flower show!
H. quercifolia (Oakleaf Hydrangea) Photo Courtesty of Andrea Schnapp
Those looking to diversify their hydrangea collection should next look to the native Oakleaf Hydrangea (H. quercifolia). The Oakleaf Hydrangea is a Florida native, growing wild on the steep, shady ravines along the northern end of the Apalachicola River. If the plants never flowered, the Oakleaf would be worth planting; its massive leaves, oak-shaped as the name suggests, can grow up to a foot in length and provide some of the best fall foliage color available to Floridians. However, the real show, as with all hydrangea species, are the flowers. This species flaunts 8”-10” white, panicle shaped flowers that are held elegantly above the coarsely textured foliage. In addition to these features, Oakleaf Hydrangeas couldn’t be easier to grow; obtaining heights up to 10’ and asking very little of the gardener other than adequate irrigation and some shade in the heat of the day! Look for the author’s favorite cultivars: ‘Alice’, ‘Semmes Beauty’, and ‘Snowflake’. Each of these cultivars and selections of the common species H. quercifolia perform very well in Northwest Florida.
H. paniculata ‘Quickfire’ Photo courtesy of Andrea Schnapp.
Finally, the newest hydrangea species introduced to Florida gardens, H. paniculata, has made significant inroads in the landscape industry over the last decade. Primarily grown as the cultivar ‘Limelight’, H. paniculata overcomes some of the weaknesses of the two aforementioned species, namely it tolerates full-sun and persists on much less water, making it a potentially more sustainable plant for many landscapes. This plant, like the remontant H. macrophylla cultivars, blooms on new wood and even seems to enjoy a hard pruning each winter; plants pruned this way seem to be more vigorous the next season and produce larger greenish-white flower panicles than unpruned specimens. Though it is a relative newcomer, H. paniculata, particularly ‘Limelight’, is a worthy addition to any landscape.
As you can see, there is a hydrangea for every yard and no true Southern landscape is complete without a few. When perusing your local garden center this summer, look for the selections and species mentioned above, plant properly, and enjoy the ensuing annual flower show for many years into the future! Who knows, you may be hooked by hydrangeas as I once was!