Caladiums [Caladium ×hortulanum Birdsey, Araceae Juss.] are ornamental aroids often used as container or landscape plants (Evans et al. 1992). They are valued for their variably shaped, bright foliage. Based on leaf type (fancy and lance-leaved) and leaf color (white, red, pink, and multicolored) (Bell et al. 1998), commercial caladium cultivars can be broadly classified into eight groups. In general, the red fancy-leaved type of caladiums account for about one-quarter to one-fifth of the field acreage planted by Florida caladium growers (Bell et al. 1998; Deng et al. 2008), which supply all the caladium tubers used by greenhouse growers, nurseries, landscapers, and gardeners across Florida, in almost every other continental state in the United States, and in some 40 countries in the world. ‘Freida Hemple’ has been the dominant cultivar among the red fancy-leaved caladiums. There has been a strong demand for new red, fancy-leaved caladium cultivars. ‘Lava Glow’ is a new caladium cultivar that was released in 2020 under the name ‘UF-15-19’ by the University of Florida Institute of Food and Agricultural Science’s caladium breeding program at the Gulf Coast Research and Education Center in Wimauma, FL. Plants of ‘Lava Glow’ produce many bright-red to red-purple heart-shaped leaves with strong sunburn tolerance and resistance to leaf spot diseases. ‘Lava Glow’ is well suited for use in containers, small to large, planted in landscapes ranging from full sun to shady locations. This cultivar has shown good tuber yield potential, its tubers are well branched, and de-eyeing may be optional for producing plants in small containers. With these characteristics, ‘Lava Glow’ can further enrich the plant palette for caladium growers, nurseries, landscapers, and gardeners. This article describes the origin and foliar features of this cultivar and provides a summary of results from replicated field, greenhouse, and garden trials.
Origin
‘Lava Glow’ originated from a cross between ‘Fire Chief’ and ‘Fairytale Princess’ that was made in Balm, FL, in Jul 2013 (Fig. 1). ‘Fairytale Princess’ was progeny of a cross between ‘Florida Sweetheart’ and ‘Red Flash’ that was made in Spring 2004 (Deng et al. 2013). ‘Fire Chief’ and ‘Red Flash’ are unpatented commercial cultivars, whereas ‘Fairytale Princess’ is a patented cultivar that was released in 2012 (Deng et al. 2013). ‘Florida Sweetheart’ (Wilfret 1991) was a patented cultivar (U.S. Plant Patent 8,526), but its patent expired. ‘Lava Glow’ was initially selected in Sep 2015 as breeding line N1403-1, which was recoded as 15-19 in Apr 2016. The ancestry of ‘Fairytale Princess’ (Deng et al. 2013) and ‘Florida Sweetheart’ (Wilfret 1991) is shown in Fig. 1. The ancestry of ‘Fire Chief’ and ‘Red Flash’ is unknown. First, asexual propagation of ‘Lava Glow’ occurred in Balm, FL, in Spring 2015; since then, it has been propagated asexually through tuber division for five generations. Plant, foliar, and growth characteristics of ‘Lava Glow’ have been stable and consistent during asexual propagation.
Description
The description of color for plant parts was based on a comparison with the Royal Horticultural Society (RHS) color chart (Royal Horticultural Society 1986). Plants used for color descriptions were grown from intact (non-de-eyed) No. 1 tubers (four per container) in 20.3-cm containers in a shaded greenhouse in Balm, FL, with ∼30% light exclusion; the air temperature inside the greenhouse was between 25 and 33 °C. The containers were filled with the commercial potting mix Pro-Line 4B (Jolly Gardener, Poland Spring, ME) amended with the commercial controlled-release fertilizer Osmocote® (15N–3.9P–10K, 5–6 months; Scotts Co., Marysville, OH) at a rate of 4.3 kg⋅m–3 and MicroMax micronutrients (ICL Fertilizers, Dublin, OH) at a rate of 0.48 kg⋅m–3.
‘Lava Glow’ plants grown from four intact No. 1 tubers in 20.3-cm containers for ∼8 weeks have an average height of 43 cm and an average width of 67 cm (Fig. 2). Mature leaves of ‘Lava Glow’ are peltate, ovate-cordate, with palmate-pinnate venation. Primary and secondary veins are red (RHS 53A to 53B). The upper surface has a green (RHS 137A) margin, up to 10 mm wide, bordering the entire leaf except for the basal leaf sinus, where it is red (RHS 53A). Interveinal areas in the center of the leaf blade are red (RHS 40B). Numerous irregular spots and blotches of variable sizes in red (RHS 40C) are located between the large red (RHS 40) center and the margin. The undersurface has a primarily red-purple (RHS 59A) center with red-purple (RHS 59B) primary veins. Numerous small blotches and spots of red-purple (RHS 61C/D) are located between the center and the margin. Petioles are dark brown (RHS 200A) streaked variably with light brown (RHS 200D), light purple (RHA 79D), and deep red-purple (RHS 59A). Tuber surfaces are gray-orange (RHS 177A/B) with the cortical area yellow-orange (RHS 15B/C).
A typical plant of ‘Lava Glow’ (35-d-old) caladium forced from four No. 1 (3.8–6.4-cm-diameter) tubers in an 8-inch container. Tubers were planted on 14 May 2020, the plant was grown in a greenhouse with ∼30% light exclusion, and the photo was taken 19 Jun 2020. (Photo by K. Druffel.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
A typical plant of ‘Lava Glow’ (35-d-old) caladium forced from four No. 1 (3.8–6.4-cm-diameter) tubers in an 8-inch container. Tubers were planted on 14 May 2020, the plant was grown in a greenhouse with ∼30% light exclusion, and the photo was taken 19 Jun 2020. (Photo by K. Druffel.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
A typical plant of ‘Lava Glow’ (35-d-old) caladium forced from four No. 1 (3.8–6.4-cm-diameter) tubers in an 8-inch container. Tubers were planted on 14 May 2020, the plant was grown in a greenhouse with ∼30% light exclusion, and the photo was taken 19 Jun 2020. (Photo by K. Druffel.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
Tuber Yield Potential
‘Lava Glow’ was evaluated for tuber yield potential in small, replicated experimental field plots in Wimauma, FL, in 2018 and 2019. The soil was EauGallie fine sand with about 1% organic matter and a pH value between 6.2 and 7.4. Caladium plants were grown in the field plots using a white plastic–mulched raised-bed system (Deng and Harbaugh 2006; Geraldson et al. 1965). In the 2018 season, ground beds (81 cm wide, 20 cm tall) were fumigated on 13 Feb with Pic-Clor 60® (39.0% 1,3-dichloropropene and 59.6% chloropicrin) at 448 kg⋅ha–1 and Prowl® H20. Caladium seed tubers were treated in hot water (50 °C) for 30 min. Seed tuber pieces were dusted with a biological fungicide (RootShield® Plus WP; BioWorks, Victor, NY) and planted manually on 27 Apr at 15-cm spacing between rows and in rows. Fifty pounds of granular nitrogen per acre was incorporated into the soil before bedding. Two drip tapes were buried under the plastic mulch along the raised beds for irrigation and fertilization. Fertigation began on 29 May, injecting a commercial liquid fertilizer (5N–0.87P–6.64K; Chemical Dynamics, Plant City, FL) at a rate of 0.454 kg nitrogen an acre a day, and was stopped on 31 Oct. New crop tubers were dug and washed on 17 Dec and air-dried for ∼50 d inside a greenhouse. Dried tubers from each experimental field plot were weighed, graded, and counted on 6 Feb 2019, as described by Deng and Harbaugh (2006). Tuber grading was by the maximum diameter: Super Mammoth, >11.4 cm; Mammoth, 8.9 to 11.4 cm; Jumbo, 6.4 to 8.9 cm; No. 1, 3.8 to 6.4 cm; and No. 2, 2.5 to 3.8 cm. Tuber grades and counts were converted into a production index to show the relative economic value of the harvested tubers per field plot: Production index = 8n (Super Mammoth) + 6n (Mammoth) + 4n (Jumbo) + 2n (No. 1) + 1n (No. 2), where n is the number of tubers in the grade. The relative values assigned to the five tuber grades in calculating the production index were based on the relative market prices provided by Florida caladium tuber producers.
For the 2019 evaluation, beds were fumigated on 24 Feb with Pic-Clor 60® at 448 kg⋅ha–1. Caladium seed pieces were planted on 4 Apr. Fifty pounds of granular nitrogen per acre was incorporated into the soil before bedding. Fertigation began on 1 Jun by injecting a commercial liquid fertilizer (5N–0.87P–6.64K, Chemical Dynamics) at 0.454 kg nitrogen an acre a day. The fertilization rate was increased to 0.908 kg nitrogen an acre a day on 24 Jul; fertilization ended on 31 Oct. Tubers were dug and washed on 9 Dec, dried in the greenhouse for ∼45 d, and weighed, graded, and counted on 21 Jan 2020 using the same protocol used in 2018.
In both growing seasons, the field plots were arranged in a randomized complete block design with three replicates. The plot size was 1.2 m2 and was planted with 30 caladium propagules (tuber pieces). ‘Freida Hemple’, a standard red, fancy-leaved caladium cultivar, was included in the field trials as a check to assess the tuber yield potential and plant performance of ‘Lava Glow’.
On average, ‘Lava Glow’ in the experimental plot in 2018 produced 1.97 kg of tubers, of which 33.3 were marketable and had a production index of 84.5 (Table 1). With these parameters, ‘Lava Glow’ was not significantly different from ‘Freida Hemple’. Similarly, ‘Lava Glow’ and ‘Freida Hemple’ were not significantly different in tuber weight (1.82 and 1.42 kg, respectively), marketable tubers (45.0 and 32.7, respectively), and production index (68.0 and 58.7, respectively) in the 2019 growing season (Table 1). The primary grade of tubers produced by ‘Lava Glow’ in 2018 and 2019 was No. 1 (44.1% in both years), followed by No. 2 (24.1% in 2018 and 53.1% in 2019), and Jumbo tubers (25.8% in 2018 and 2.7% in 2019). This tuber size distribution was not significantly different from that of ‘Freida Hemple’. Thus, in terms of tuber yield potential, ‘Lava Glow’ was comparable to ‘Freida Hemple’, one of the main red, fancy-leaved cultivars in commercial caladium tuber production.
Tuber weight, number of marketable tubers, production index, and grade distribution of ‘Lava Glow’ and commercial caladium cultivar Freida Hemple (check).
Container Trials
The suitability of ‘Lava Glow’ for container plant production was evaluated in 2020 by forcing tubers in 12.7-cm containers (diameter) by following the protocol of Harbaugh and Tjia (1985). No. 1 tubers (intact or de-eyed) were planted on 1 May 2020 in the commercial potting mix Pro-Line 4B (Jolly Gardener) amended with Osmocote® fertilizer (15N–3.9P–10K, 5–6 months) at 4.3 kg⋅m–3 and Micromax (ICL Fertilizers) at 0.48 kg⋅m–3. Potted tubers and plants were grown in a greenhouse with ∼30% light exclusion. Temperatures in the greenhouse ranged from 25 °C (night) to 33 °C (day). Potted tubers and plants were arranged on metal benches, with a pot-to-pot spacing of 0.4 m, in the greenhouse in a randomized complete block design with seven replicates. Two red, fancy-leaved commercial cultivars, Brandywine and Freida Hemple, were included as checks for ‘Lava Glow’. Fungicide Subdue Maxx (Syngenta Group Co., Basel, Switzerland) was applied as a drench to all potted plants on 4 Jun 2020. Plant height, plant width, number of leaves, and foliar characteristics were recorded on 23 and 24 Jun 2020, ∼8 weeks after planting. Quality of the potted caladium plants was rated on a scale of 1 to 5, with 1 = very poor, unattractive, totally unacceptable as potted plants with few leaves; and 5 = very attractive, full plants with a symmetric shape, an appropriate height, and many bright, colorful leaves. Analysis of variance and mean comparisons were performed using JMP Pro 15.0.0 (SAS Institute Inc., Cary, NC).
Intact tubers of ‘Lava Glow’ sprouted 28 d after planting, about 12 to 13 d later than ‘Brandywine’ or ‘Frieda Hemple’ (Table 2). De-eyed tubers of ‘Lava Glow’ sprouted 32 d after planting, about 9 to 10 d later than ‘Brandywine’ or ‘Freida Hemple’ (Table 2). Plants of ‘Lava Glow’ forced from intact No. 1 tubers had an average height of 31.0 cm, an average width of 39.2 cm, and an average of 20 leaves, and, on average, the leaves were 25.1 cm long and 16.9 cm wide (Fig. 3). Plants forced from de-eyed No. 1 tubers were 23.1 cm tall and 33.4 cm wide and had about 20 leaves, and the leaves were 16.0 cm long and 10.5 cm wide. ‘Lava Glow’ and the two checks, ‘Brandywine’ and ‘Freida Hemple’, were not significantly different in plant height, number of leaves, leaf length, and leaf width, except they were significantly different in plant width (Table 2). Plants of ‘Lava Glow’ were about 7 cm narrower than plants of ‘Brandywine’ or ‘Freida Hemple’. Plants of ‘Lava Glow’ from intact tubers received a quality rating of 3.9 (on a scale of 1 to 5), which is significantly greater than the plant quality rating of ‘Brandywine’ or ‘Freida Hemple’ (Table 2). Plants of ‘Lava Glow’ from de-eyed tubers received a quality rating of 3.4, not significantly different from that of the two checks. In general, de-eyed tubers produce higher quality pot plants. However, this was not observed with de-eyed ‘Lava Glow’ tubers. This was because de-eyeing delayed color development on ‘Lava Glow’ leaves (Fig. 3).
Plants of ‘Lava Glow’ caladium forced from one intact (left) or de-eyed (right) No. 1 (3.8–6.4-cm-diameter) tuber in a small container (diameter, 12.7 cm). Tubers were planted on 1 May 2020, plants were grown in a greenhouse with ∼30% light exclusion, and the photo was taken 22 Jun 2020. (Photo by K. Druffel.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
Plants of ‘Lava Glow’ caladium forced from one intact (left) or de-eyed (right) No. 1 (3.8–6.4-cm-diameter) tuber in a small container (diameter, 12.7 cm). Tubers were planted on 1 May 2020, plants were grown in a greenhouse with ∼30% light exclusion, and the photo was taken 22 Jun 2020. (Photo by K. Druffel.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
Plants of ‘Lava Glow’ caladium forced from one intact (left) or de-eyed (right) No. 1 (3.8–6.4-cm-diameter) tuber in a small container (diameter, 12.7 cm). Tubers were planted on 1 May 2020, plants were grown in a greenhouse with ∼30% light exclusion, and the photo was taken 22 Jun 2020. (Photo by K. Druffel.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
Days to sprout, plant height, plant width, leaf number, leaf length, leaf width, number of blooms (inflorescences), and plant quality ratings of ‘Lava Glow’ and commercial caladium cultivars Brandywine and Freida Hemple (checks) grown in small containers.
Plant Performance in Open Fields in Full Sun
‘Lava Glow’ was evaluated for plant growth, leaf color display, sunburn tolerance, and leaf health in the same field plots used for evaluating tuber production. Growing conditions are were described earlier. Rating scales were the same as described previously (Deng and Harbaugh 2006). Briefly, a scale of 1 to 5 was used for rating plant growth, with 1 being very poor (few leaves and lack of vigor) and 5 being excellent (full plants, numerous leaves). A scale of 1 to 5 was used for rating leaf color display, with 1 being very poor (dull or bleached, lack of color display) and 5 being excellent (bright, very attractive). Sunburn tolerance was evaluated on a scale of 1 to 5, with 1 being very susceptible to sunburn (leaves having numerous sun-damaged areas or holes) and 5 being resistant to sunburn (no visible sun-damaged areas). Leaf health was evaluated on a scale of 1 to 5, with 1 being numerous diseased spots and completely unsightly, and 5 being healthy and free of visible leaf spot disease. Evaluations of plant growth, leaf color, sunburn tolerance, and leaf health were done on 13 Aug, 10 Sep, 1 Oct, and 24 Oct 2014; 13 Aug, 4 Sep, and 15 Oct 2015; 27 Jul and 25 Aug 2018; 13 Jul, 13 Aug, and 18 Sep 2019; and/or 31 Jul, 21 Aug, and 20 Sep 2020.
‘Lava Glow’ plants received growth scores of 2.0 to 3.8 in the 2018 and 2019 growing seasons (Table 3), which were significantly greater than ‘Freida Hemple’ scores in two of five evaluations. Leaf color rating of ‘Lava Glow’ ranged from 2.8 to 4.3, which was significantly greater than that of ‘Freida Hemple’ in three of five evaluations (Table 3). Sun tolerance ratings of ‘Lava Glow’ plants were between 3.3 and 4.8, which were significantly greater than the rating scores of ‘Freida Hemple’ in two of five evaluations (Table 4). Leaves of ‘Lava Glow’ had few diseased spots and received health scores between 3.3 and 4.7, which were significantly greater than the leaf health scores of ‘Freida Hemple’ in two of five evaluations (Table 4).
Plant growth and leaf color rating of ‘Lava Glow’ and commercial caladium cultivar Freida Hemple (check).
Sunburn tolerance and leaf health rating of ‘Lava Glow’ and commercial caladium cultivar Freida Hemple (check).
Plant Performance in Garden Trials
Two garden trials, one in full sun and one in shade, were conducted in Summer 2020 to evaluate the plant performance of ‘Lava Glow’ against the commercial cultivar Brandywine. Garden beds were mulched, with a black landscape cover. Two drip tapes were laid below the landscape cover to provide irrigation. For each cultivar, three No. 1 intact tubers (diameter, 6.4–8.9 cm) were planted in the beds (one tuber per replicate) on 22 May 2020, with a spacing of ∼0.75 m. Fifteen grams of the controlled release fertilizer Osmocote® (15N–3.9P–10K, 5–6 months) were applied to each plant. Data were acquired on leaf number, and leaf length and width on 17 Jul (∼2 months postplanting) and 14 Aug 2020 (∼3 months postplanting). Plants were rated on a scale of 1 to 5 for plant growth, leaf color display, sunburn tolerance, and leaf health, as described earlier.
‘Lava Glow’ plants performed well under shade (Fig. 4) and in full sun (Fig. 5), receiving plant growth scores of 4.0 to 4.7 and leaf color scores of 2.7 to 3.7 (Table 5). It did a little bit better in full sun than under shade, receiving greater plant growth and leaf color scores in full sun than in shade. When grown in full sun, ‘Lava Glow’ plants showed great er sunburn tolerance and fewer leaf disease symptoms (greater leaf health ratings) than ‘Brandywine’. Leaves were 4 to 6 cm shorter and 2 to 3 cm narrower than ‘Brandywine’ leaves (differences were significant at P = 0.0574–0.0832) (Table 5). When grown in shade, ‘UF-15-19’ was not significantly different from ‘Brandywine’ in plant height, width, leaf number, leaf length and width, sunburn tolerance, or leaf health, regardless of whether they were evaluated 2 or 3 months postplanting (Table 5).
Typical leaves of ‘Lava Glow’ caladium (∼8 weeks old) grown under shade in Wimauma, FL. The plant was grown from one No. 1 tuber that was planted 22 May 2020; the photo was taken 16 Jul 2020. (Photo by K. Druffel.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
Typical leaves of ‘Lava Glow’ caladium (∼8 weeks old) grown under shade in Wimauma, FL. The plant was grown from one No. 1 tuber that was planted 22 May 2020; the photo was taken 16 Jul 2020. (Photo by K. Druffel.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
Typical leaves of ‘Lava Glow’ caladium (∼8 weeks old) grown under shade in Wimauma, FL. The plant was grown from one No. 1 tuber that was planted 22 May 2020; the photo was taken 16 Jul 2020. (Photo by K. Druffel.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
Typical leaves of ‘Lava Glow’ caladium in an open field in full sun. Photo taken in Lake Placid, FL, 13 Sep 2019. (Photo by Z. Deng.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
Typical leaves of ‘Lava Glow’ caladium in an open field in full sun. Photo taken in Lake Placid, FL, 13 Sep 2019. (Photo by Z. Deng.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
Typical leaves of ‘Lava Glow’ caladium in an open field in full sun. Photo taken in Lake Placid, FL, 13 Sep 2019. (Photo by Z. Deng.)
Citation: HortScience 58, 1; 10.21273/HORTSCI16937-22
Plant size, growth rating, leaf size, and leaf color rating of ‘Lava Glow’ and commercial caladium cultivar Brandywine (check) in sun and shade garden trials in Balm, FL, in 2020.
Conclusion
‘Lava Glow’ is a new red, fancy-leaved caladium cultivar with a novel color and coloration pattern. In container trials, ‘Lava Glow’ performed well and produced attractive plants even without tuber de-eyeing treatment. In garden trials, this cultivar performed well and showed strong sunburn tolerance and resistance to leaf spot diseases. In field trials, ‘Lava Glow’ demonstrated good tuber yield potential, and its tubers were well branched. With thesecharacteristics, ‘Lava Glow’ is an important new addition to the red fancy-leaved caladium cultivar group.
The research and evaluations reported here were performed on small acreages and/or small numbers of plants. Caladium tuber producers are encouraged to plant only limited quantities of this cultivar until having gained experience in producing ‘Lava Glow’. Standard postharvest treatment of tubers is recommended (Harbaugh and Tjia 1985) and preplant hot-water treatment of tubers is encouraged to prolong their life (Rhodes 1964).
Availability
A plant patent will be applied for ‘Lava Glow’. Commercial production of this cultivar is required to have a licensing agreement with Florida Foundation Seed Producers, Inc., P.O. Box 309, Greenwood, FL 32443. Information on tuber availability and licensing agreements can be obtained from Florida Foundation Seed Producers, Inc. (http://www.ffsp.net/).
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