Perennial rhizomatous begonias add bold texture and color to north Florida gardens

Perennial rhizomatous begonias add bold texture and color to north Florida gardens

Article by Dr. Gary Knox, Professor of Environmental Horticulture at the UF/IFAS NFREC Quincy

Introduction

Rhizomatous begonias are a large group of Begonia species, hybrids and selections characterized by large, sometimes-colorful leaves arising from thick rhizomes that grow along the soil surface. White or pink flower clusters that appear in late winter and spring are an extra bonus with these plants. Some types can be used in north Florida as herbaceous perennials that add bold leaf texture and color as well as flowers to shady gardens.

Begonia mass planting

Common rhizomatous begonias such as Begonia nelumbiifolia, ‘Erythrophylla’ (“Beefsteak”), and ‘Ricinifolia’ have long been grown outdoors in south and central Florida gardens as herbaceous perennials. North of these areas, rhizomatous begonias were considered cold sensitive and thus used strictly as pot-grown plants grown indoors or protected over winter. Nonetheless, north Florida trials testing the performance of outdoor, in-ground plantings started in Tallahassee and Gainesville as long ago as the late 1980s and early 1990s. With the proven success of some rhizomatous begonias in north Florida, interest in these plants increased rapidly in the early 2000s. Since then, savvy north Florida gardeners have been delighted by the possibility of using rhizomatous begonias as interesting herbaceous perennials for the shade garden. While temperatures below freezing can damage or kill leaves, these plants will usually produce new leaves from the rhizomes once warmer temperatures return in spring.

Plant Description Under North Florida Conditions

Leaves of rhizomatous begonias are this plant’s most distinctive feature and are why this group is so appealing to gardeners. Leaves often are large, from a few inches wide to almost 3 ft. in diameter (as reported for the cultivar ‘Freddie’ under the right conditions). Leaf shape may be rounded, star-shaped or irregularly edged, and leaf colors include burgundy, red, bronze, chartreuse, silver, and various shades of green including one so dark as to be almost black. Many types have leaves displaying patterns of one or more colors and some have silver or red markings. Undersides of leaves are often burgundy-colored, and leaf stems (petioles) also may exhibit colors other than or in addition to green. Leaves may be smooth, textured, or fuzzy-appearing due to large numbers of sometimes conspicuous hairs. Some types have leaves with an interesting three-dimensional spiral located on top of the leaf where the leaf blade attaches to the stem.

Begonia ‘Big Mac’ foliage

Rhizomatous begonia rhizomes are thickened, fleshy stems 1 to 2 in. or more in diameter that grow, branch and spread horizontally at or just below the soil surface, often in the mulch or leaf duff. Adventitious roots develop along the rhizome, and dormant buds embedded in the horizontal stem can be stimulated to grow new leaves after damage, stress or when divided. With age, as rhizomes grow outward, the oldest part of the rhizome will stop producing leaves and eventually die.

The rhizomes contain water and food reserves that allow this type of begonia to survive environmental stresses like drought as well as leaf loss or damage from cold temperatures. Shoots and roots can grow from the rhizome even if leaves and roots are killed or damaged.

Flowers occur in late winter to spring, depending on the species, cultivar and weather, and are quite showy on some selections. Flowers typically are white to various shades of pink and occur in a cluster (technically called a cyme) held above the foliage, in some cases dramatically high above the foliage. Individual flowers may range in size from 3/8-inch to over 2 inches at their widest point and a flower cluster may contain a few to over 120 individual flowers, depending on selection and growing conditions. A mature rhizomatous begonia may have an extended period of flowering, providing weeks of color. This long floral display results from large numbers of flowers developing sequentially on an individual flower cluster such that new flowers are still forming long after the first flowers have opened. Furthermore, multiple flower clusters appear over an extended time period. Flowers occasionally are pollinated and form winged seed capsules, though seed production and viability are variable. After flowering, the leaves remain a point of interest in the garden due to their size, lush appearance, interesting shapes and colorful patterns.

Cultural Requirements, Use and Maintenance

Rhizomatous begonias grow best in light shade or indirect light but can tolerate morning sun. Plants thrive in rich, organic, well-drained soil that is moist but not wet. A layer of organic mulch or leaf litter often is enough to provide basic conditions for growth in most soils if they are well-drained. Accordingly, organic mulches or leaf litter should be applied regularly around plants. Fertilizer stimulates growth but decomposing organic mulches can provide adequate nutrients, except perhaps with poor or sandy soils.

Newly planted begonias should be watered regularly. After establishment, most rhizomatous begonias benefit from regular watering but only require irrigation during periods of drought or extended dry weather.

An individual plant makes an attractive specimen plant in a container or in the garden. With time, a rhizomatous begonia can spread and, in the garden, develop into a patch. Alternatively, planting large numbers of the same rhizomatous begonia can create a very dramatic garden border, mass planting, or groundcover, especially in spring when all plants are flowering. To achieve this effect more rapidly and with smaller numbers of plants, tips of rhizomes can be pruned to stimulate rhizome branching and result in a denser plant or patch. Rhizome tip pruning should be done after plants finish flowering. Plants can be divided and moved easily since only the rhizome is needed to establish a new plant, but this should occur after flowering and early in the growing season so plants have long enough to establish before cold weather.

For aesthetic purposes, dead or damaged leaves may be removed as needed but especially after frosts and hard freezes. Similarly, leaves that overwinter often become “ratty” in appearance with time and may be removed without affecting plant growth.

Potential Problems

Rhizomatous begonias have few pests or other problems. Mealy bugs can occasionally infest plants. As with other large-leaved plants, wind or physical contact can tear and damage leaves. In north Florida, winter frosts and freezes can damage and disfigure leaves or kill leaves entirely, causing them to lose structural integrity and collapse, appearing mushy. Foliage may be protected during cold weather by frost cloth, sheets or other typical cold protection strategies, though heavy coverings could themselves damage leaves.

Rhizomes themselves usually survive cold weather because they are insulated from low temperatures by being half-buried in the ground and/or being covered by mulch. Adding mulch regularly to rhizomatous begonia plants will provide increased freeze-protection. Also, their typical planting location under tree canopies protects plants from a radiation freeze. Soil drainage is a more important factor for rhizomes since wet soil conditions could lead to rot, particularly in winter.

Common Types and their Descriptions Under North Florida Conditions

With hundreds of species and thousands of cultivars and hybrids, rhizomatous begonias can be overwhelming. Many rhizomatous begonias look alike and even experts have difficulty distinguishing species and cultivars. Many grown in north Florida have their origins in Mexico, Central and South America, though the Begonia Family is huge and species are found nearly world-wide.

Begonia heracleifolia

Technically rhizomatous begonias include Rex begonias, a group derived from Asian native, Begonia rex, and known for their especially colorful leaves. However, most Rex begonias do not grow well in Florida’s heat, high rainfall and high humidity, and so these begonias are excluded here.

Begonias listed below represent types that have proven resilient and usually cold hardy in north Florida USDA Cold Hardiness Zone 8b.

Species:

Begonia heracleifolia: The species boasts star-shaped leaves up to 6 in. across on stiff, hairy, thick leaf stems (petioles) up to 5 in. long. Each of the pointed leaf lobes is edged in dark green and has a chartreuse stripe along the central midrib, adding contrast. Spectacular sprays of pale pink flowers appear in late winter in clusters measuring 3 ½ in. by 4 ½ in. on 6-in. flower stalks (pedicels). Each cluster contains about 30 or more flowers, each about 1 in. across. As the season goes on, foliage gets showier and showier. It often dies down after winter freezes but re-emerges in late spring.

Begonia nelumbiifolia

  1. nelumbiifolia: This cold hardy begonia is known for its exceptionally large, water lotus-shaped leaves, creating a stunning specimen. Individual leaves can grow as large as 18 in. by 14 in. on leaf stems as long as 36 in. but 12 in. by 9 in. leaves are more typical. As temperatures warm, new developing foliage continues to get bigger, growing into very large leaves by fall. There also is a form in which the medium green leaves have red veining. White flowers are displayed above the foliage in mid to late spring in airy clusters measuring 7 ½ in. to more than 12 in. across on stems up to 48 in. tall. Clusters may contain as many as an astounding 120 flowers, each about ¾ in. across at its widest point.

2. popenoei: Huge rounded leaves with red veins and undersides make this a specimen plant which can grow to 3 ½ ft. tall and wide. Hardy with protection, it throws up tall stalks with clusters of white flowers in late winter.

Cultivars:

“Beefsteak”: This catch-all name refers to the original beefsteak begonia, ‘Erythrophylla’, as well as many derivatives that look similar. Beefsteak begonias characteristically have rounded leaves with a glossy green to bronze top surface and reddish undersides. Leaves range in size from 4 to 7 in. in diameter, and flower clusters are on stems up to 18 in. tall. ‘Erythrophylla’ was developed in 1847 and is considered a tough, vigorous plant, hence the common name, “beefsteak”. Given the long history and vigor, ‘Erythrophylla’ and derivative beefsteak begonias have long been shared as pass-along plants, world-wide as potted plants and later as an in-ground Florida garden plant. One type has ruddy, evergreen leaves and long-lasting, bold pink flower clusters. The scalloped 4-in leaves are on short 5 ½ in. reddish leaf stems but are most notable for remaining undamaged by temperatures down to the mid 20s °F, long after all other begonias’ leaves have turned to mush. Mid spring finds this plant topped by numerous clusters of dark pink flowers, with the display lasting 6 weeks or more. Individual clusters are about 8 in. by 5 in. on flower stems about 12 in. tall. Each cluster contains about 20 flowers each about ¾ in. wide at its widest point.

Begonia ‘Big Mac’ in flower

‘Big Mac’: This is a large, vigorous plant with enormous star-shaped leaves having reddish undertones and red leaf stems. The plant grows about 3 ft. tall and 2 ft. wide. Individual leaves may grow up to 18 in. wide on 16-in. leaf stems but typical leaves on younger plants are 10 in. to 12 in. wide. Individual white flowers are an amazing 2 in. wide at their widest point in clusters measuring 7 in. by 12 in. and containing about 75 flowers. Cold winters will knock it to the ground, but this begonia re-emerges again in late spring. This plant was hybridized in 1982 by Paul P. Lowe in Lake Park, Florida.

‘Joe Hayden’: This begonia features dramatic, dark, lobed leaves with burgundy undersides. Leaves are up to 8 in. long supported by leaf stems up to 9 in. long. In spring, the plant is topped by light pink flowers held high above the foliage. Each cluster measures about 5 in. by 7 in. on flower stems up to 26 in. tall. Each cluster contains more than 100 individual flowers, each about ¾ in. across at its widest point. This selection was hybridized in California in 1953 by Rudolf Ziesenhenne, but many similar selections have been made and are often confused with ‘Joe Hayden’.

Begonia ‘Joe Hayden’

Many other cultivars are common, but other cold hardy types suitable for north Florida include ‘Caribbean King’, ‘Caribbean Queen’, ‘Washington State’ and the catch-all ‘Ricinifolia’ types (with large, castor bean-shaped leaves). New breeding by scientists and enthusiasts promises to deliver many more types of rhizomatous begonias with increased foliage cold hardiness and an expanded range of foliage types and colors. A major Texas nursery introduced a series of rhizomatous begonia hybrids marketed as Crown Jewel Begonia™. The series currently features five patent-pending cultivars that are promoted as landscape plants for Zone 8. Additional breeding work is ongoing in north Florida.

Availability and Propagation

Rhizomatous begonias are available from Internet/mail order nurseries, some American Begonia Society members, other gardening groups, and plant societies. The introduction of trademarked rhizomatous begonias like Crown Jewel Begonia™ show promise for wider availability of rhizomatous begonias from nurseries.

Rhizomatous begonias are easily propagated by division, separation of rhizomes, or by rhizome pieces. When planting, place the rhizome or pieces (as small as 2 in. long) horizontally and half buried in a new in-ground location or in a container with potting soil. As with other begonia species, leaves may be used for propagation, though this method usually takes longer to achieve a size suitable for planting in the garden. Plants can be grown from seeds but production time is similarly long.

References:

American Begonia Society. (2020) https://www.begonias.org/index.htm. Accessed 15 April 2020.

Ginori, Julian, Heqiang Huo, and Caroline R. Warwick. (2020) A Beginner’s Guide to Begonias: Classification and Diversity, ENH1317. Environmental Horticulture Department, UF/IFAS Extension. January 2020. https://edis.ifas.ufl.edu/ep581.

Lowe, Paul. (1991) Growing Rhizomatous Begonias in the Ground in Southern Florida. Begonian 58:89. May/June 1991. https://www.begonias.org/Articles/Vol58/GrowingRhizomatousBegoniasFlorida.htm.

Schoellhorn, R. (2020) Personal communication, Alachua, FL.

Sharp, Peter G. (2011) Down to Earth – with begonias. 111 pp. http://ibegonias.filemakerstudio.com.au/PeterSharp/DownToEarthWithBegonias.pdf.

The International Database of the BEGONIACEAE. (2020) http://ibegonias.filemakerstudio.com.au/index.php?-link=Home. Accessed 16 April 2020.

UF/IFAS Gardening Solutions. (2019) Begonias. http://gardeningsolutions.ifas.ufl.edu/plants/ornamentals/begonias.html.

Watkins, Sue. (2020) Personal communication, Tallahassee, FL.

Japanese Plum Yews for the Landscape

Japanese Plum Yews for the Landscape

We are always on the lookout for an attractive plant for our landscape.  At the nursery, some plants have a more difficult time gaining our attention. They may not be as showy, possessing neither colorful flowers nor bold foliage.  In these cases, we could be missing out on low maintenance plant that offers its own form of beauty in the right landscape spot.
One plant that I love is the Japanese plum yew (Cephalotaxus harringtonia), especially the spreading form ‘Prostrata’.  In the nursery container, this plant is nothing special but once established in the landscape it performs well.  The conifer type leaves are an attractive dark green and the ‘Prostrata’ selection is low growing to about 2 to 3 feet.  An advantage too is that growth is slow so it won’t take over or require routine pruning.
Japanese plum yews grow best in partial shade and once established will be fine with rainfall.  For a shadier side of the home, the spreading plum yew has a place as an evergreen foundation plant too.

Japanese plum yew in a shaded garden. Photo by Beth Bolles, UF IFAS Extension Escambia County

If the ‘Prostrata’ selection is too low growing for you, consider the ‘Fastigiata’ cultivar that will grow upright to about 8 feet with a 5 foot spread.

A year old planting of upright Japanese plum yew in filtered light. Photo by Beth Bolles, UF IFAS Extension Escambia County

Perennial Peanut Lawn:  Two Years Later

Perennial Peanut Lawn:  Two Years Later

‘Needlepoint’ Perennial Peanut in the author’s lawn.

What began as my journey toward a turf-less lawn in September of 2017 is finally beginning to come together!  In the fall of 2017, I installed about 120 one-gallon-sized ‘Needlepoint’ Perennial Peanut (Arachis glabrata) plants, purchased from Sunset Specialty Groundcovers in Live Oak, FL, on roughly 20” centers in my front lawn, an oddly shaped (650 ft2) patch of ground that had been previously filled with spotty centipedegrass and a healthy and diverse weed population.  18 months later, the peanut has almost completely filled in, shaded out all the weeds, and blooms nonstop!

Looking back, I definitely learned a few lessons the hard way.  First, you should mulch bare ground in between plants at time of installation.  Because there are few herbicides labelled for residential use on this crop and I didn’t want to experiment on my new “lawn”, I spent a lot of time on my hands and knees (much to the amusement of my neighbors and folks driving by) pulling weeds in the first two years that could have been prevented with mulch.  Second, have a plan for keeping the perennial peanut in bounds once it has filled in the area it was supposed to and begins to travel into adjacent landscaped beds!  The area my peanut inhabits is surrounded on two sides by inescapable concrete.  It was on the other two sides, however, that I have had to improvise after they came under siege (literally under, because perennial peanut spreads by underground rhizomes).  Installing some sort of edge blocker at planting and vigilance with routine mechanical edging is a must to keep it in bounds!  Third, I recommend that you have a counter-argument prepared when the peanut goes dormant in the winter and your wife asks why the yard is bare dirt!

‘Needlepoint’ Perennial Peanut overhead shot showing complete ground coverage in the author’s lawn.

Overall, though there are a couple of things I would have done differently, I’m extremely pleased with my lawn of perennial peanut.  It is absolutely stunning in the warm months, incredibly low maintenance, and unique!  Plant some today!

As always, if you have any questions about perennial peanut or any other plant/crop, contact your local UF/IFAS Extension office.

Improving Soil Health, Suppressing Weeds, and Attracting Good Bugs

Improving Soil Health, Suppressing Weeds, and Attracting Good Bugs

Many gardeners plant a spring vegetable garden with a number of different vegetable types, which is excellent because a diverse and varied garden is proven to improve soil health. Intercropping is a gardening practice of growing different crops in the same field.  When planting a mixture of crops in the same field year after year, it is important to rotate the location of each type of vegetable.  This is a practice known as crop rotation.  Intercropping and crop rotation will help reduce insect pest populations, increase beneficial insect populations, and reduce weed populations .

Crop Diversity

Including plants that pest insects don’t like to eat in a garden forces the pests work harder to find what they find palatable. Studies have found reduced whitefly numbers on squash plantings mixed with a crop of buckwheat when compared to squash planted alone.  Another crop mixture that may be unintentional, but may be favorable, is a crapemyrtle stand along a garden’s edge.  Crapemyrtles will attract the crapemyrtle aphid which will attract predatory insects. When the predatory insects run out of crapemyrtle aphids to eat, they will move to the vegetable garden and begin to hunt pest insects.

Squash with living mulch of buckwheat. Photo Credit: Oscar Liburd, UF/IFAS Extension

Trap Cropping

A trap crop is a plant that attracts a pest insect away from your food crops.  Trap crops work best when planted at the garden’s edge, along a fence row, or in movable containers.  A bare space, let’s say 5 feet or so, should be kept between trap crops and vegetable plantings.  This will help keep the pests from moving desirable crops plants.  When a large population of pests are found on the trap crop then it is time to spray them with insecticide, or cut the crop down and remove or destroy the debris. If trap crops are planted in containers, then it makes them much easier to remove from the garden when necessary.

Cover Crops and Green Manure

Soil organic matter can be increased by the use of green manure and cover crops.  Cover crops are generally planted during the off-season, but they can be planted in between vegetable rows and tilled in at a designated time as a green manure.  Both cover crops and green manure improve garden production by:

  • Suppressing weeds by competing for water, light, and nutrients;
  • Holding the soil in place and preventing erosion;
  • Scavenging for nutrients that can be utilized in future crops;
  • Reducing nematode populations;
  • Providing a habitat for beneficial insects.

A mixed plot of cover crops and trap crops. Photo Credit: Matt Lollar, UF/IFAS Extension – Santa Rosa County

A number of different crops can serve as cover crops or green manure crops.  Most are legumes (bean family) or grasses.  A few that should be tried are:

  • Cowpeas
  • Sunn hemp
  • Sorghum-sudangrass
  • Winter rye

More detailed information on cover crops and green manure can be found at this link: http://edis.ifas.ufl.edu/aa217.

Applying Florida Friendly Landscaping™ Principles During Hurricane Recovery

Applying Florida Friendly Landscaping™ Principles During Hurricane Recovery

Tree debris snowman

Storm debris turned into holiday cheer in Bayou George. Photo: J_McConnell, UF/IFAS

By the time this article publishes, we will be more than 70 days since Hurricane Michael toppled or damaged an incredible number of trees in the Panhandle. Enormous piles of once stately shade trees line the streets in neighborhoods and business districts in. The cleanup efforts have been phenomenal, over 4 million cubic yards of storm debris picked up in Bay County to date, but there is still a long way to go in the recovery process.

So, as gardeners, how can you help our community get back on track amidst your own struggles to recover? A few Florida Friendly Landscaping™ Principles come to mind.

  • #1 Right Plant, Right Place – as you rebuild your landscapes, make sure to choose the appropriate plant for the location. Consider mature size and give those plants space to thrive!
  • #4 Mulch – do you have bare ground that will eventually become landscape beds or turf but no resources or time to replant yet? Consider mulching the area to keep soil from eroding and to help improve soil though decomposition of natural products. Hint – see Recycling for free sources!
    • Mulch tips https://sfyl.ifas.ufl.edu/media/MulchBrochure.pdf
      • keep mulch 12 inches from tree trunks
      • recommended depth in beds or under dripline of tree canopy (excluding within 12” of trunk) is 2-3 inches
      • leave an 18-24 inch buffer around building foundations mulch free to reduce conducive termite conditions
  • Potted plant on stump

    Dress up stumps with plants and whimsical designs. Photo: D_VanderMeer, UF/IFAS Master Gardener

    #7 Recycle – driving around town I have seen some really creative uses for stumps, trunks, and branches that homeowners have constructed and messages of hope that bring a smile to my face. Another method of recycling is to use the chipped vegetative debris as mulch, either available as “utility mulch” by cities and counties or you may have some in your own yard right now.

    • Utility mulch does come with some words of caution because there is an increased risk of introducing weeds to your landscape with untreated storm debris. However, if you need mulch for pathways or planting beds you will be helping your community’s cleanup effort by reducing waste accumulation. Just watch for “volunteer” plants and manage as needed.

In Bay County, there are 4 locations where you can load and haul off your own utility mulch from storm debris

  • Under the Oaks Park – 5843 E. U.S. 98, Panama City, FL 32404
  • G. Harder’s Park – 8110 John Pitts Rd., Panama City, FL 32401
  • Chapman Park – 2526 Rollins Ave., Bayou George, FL 32404
  • Laird Park – 6310 Laird Park Rd., Panama City, FL 3240

For sources in your county, check with your Solid Waste Department for utility mulch availability.