Search Results

You are looking at 21 - 30 of 73 items for :

  • Refine by Access: All x
Clear All
Free access

Jules Janick

including dahlia, fuchsia, helianthus, and petunia have become very important in floriculture and are now grown worldwide. Helianthus, the sunflower, has long been associated with America as a food and medicinal plant and became an important ornamental and

Free access

Harlene Hatterman-Valenti*

Greenhouse studies were conducted to evaluate simulated drift injury to annual bedding plants. Dahlia, gazania, geranium, marigold, petunia, and salvia in the early stages of flowering were sprayed with either 2,4-D (dimethylamine salt) or dicamba (diglycolamine salt) at rates one-fifth, one-tenth, or one-twentieth the lowest labeled rate of for turfgrass. Interactions between species by time, species by treatments, and treatments by time were significant for visual injury. Species sensitivity from most sensitive to least sensitive was marigold > dahlia ≫ geranium = petunia > gazania = salvia. Dahlia was more sensitive to dicamba than 2,4-D while the opposite was true for marigold. Petunia flower initiation was reduced as dicamba or 2,4-D rate was increased. The duration of the trial may have limited flowering differences among treatments with the remaining species. Dahlia loss of apical dominance as an injury response was greater with dicamba than 2,4-D. Typical injury symptoms for dahlia included stem, leaf, and petiole epinasty along with multiple shoot growth. Gazania injury included slight leaf rolling and leaf stretching. Geranium injury included leaf curling and fewer flowers per cluster. Marigold injury included leaf node swelling and stem wall rupture with massive cellular proliferation. Petunia injury included stem and pedicel epinasty, curling of the outer portion of the corolla, and lower flower production. Salvia injury included stunting, slight flower stem curvature, and partial dieback of the terminal raceme.

Free access

Neil O. Anderson and Richard T. Olsen

Crinum followed by Lilium , Hemerocallis , Watsonia , Papaver , Gladiolus , Dahlia , and Rosa ( Table 1 ). Two of Burbank’s outstanding ornamental and/or edible herbaceous cultivars—the shasta daisy and spineless cacti (discussed below

Free access

James E. Klett and David Staats

Herbicides were applied to container grown landscape plants and evaluated on the basis of weed control, phytotoxicity, and effect on plant growth. Three preemergent herbicides were applied including: Oxadiazon (Ronstar) at 4.54 and 9.08 kg/ha, Oxyfluorfen + Oryzalin (Rout) at 3.41 and 6.81 kg/ha and Oryzalin (Surflan) at 2.27 and 4.54 kg/ha. There was also a weedy and non-weedy control. The plant species included: Syringa vulgaris (Common Lilac), Wisteria sinensis (Chinese Wisteria), Phlox paniculata (Garden Phlox) and Dahlia hybrid (Garden Dahlia). They were all grown in number one containers in a media of soil, spaghnum peat moss, and plaster sand (1:2:1 by volume). All herbicides tested controlled weeds effectively with no phytotoxicity except with Phlox paniculata. Oryzalin resulted in a phytotoxic effect on Phlox paniculata at both the 1x and 2x rates.

Free access

Raphael A. Stern and Shmuel Gazit

Contribution from MIGAL. We thank Hillary Voet for her valuable assistance in the statistical analysis and Dahlia Eisenstein for her valuable technical assistance. The cost of publishing this paper was defrayed in part by the payment of page charges

Free access

Harlene Hatterman-Valenti and Paul Mayland

Greenhouse experiments were conducted to compare visible injury from sublethal rates of 2,4-D, dicamba, and a premixed product of 2,4-D + mecoprop + dicamba for eight annual flowers and to describe herbicide injury symptoms for these annual species. Herbicides were applied at rates 0.05×, 0.1×, and 0.2× of their highest labeled rate for turfgrass to simulate spray drift conditions. Visible injury varied between species, herbicide rate, and time after herbicide application. Alyssum (Lobularia maritima Desv.) showed the greatest initial injury and ageratum (Ageratum houstonianum Mill.) showed the greatest injury at 4 weeks after treatment. Symptom severity increased as herbicide rate increased, with the greatest injury from the premixed product, followed by 2,4-D, and then dicamba. The eight species varied in their degree of visible injury and flower production to dicamba, 2,4-D, and the premixed product. Reduced flowering was most obvious for prolific flowering species such as alyssum. Impatiens (Impatiens wallerana L.), salvia (Salvia splendens Sello), and snapdragon (Antirrhinum majus L.) produced more flowers in response to sublethal dicamba rates compared to the untreated plant. All rates of 2,4-D generally reduced flowering compared to untreated plants, except the lowest rate of 2,4-D for geranium (Pelargonium xhortorum Bailey) and snapdragon. Dahlia (Dahlia hortensis Cav.) sprayed with dicamba at the highest rate produced three times as many stems as plants untreated or those sprayed with 2,4-D. Overall order of species susceptibility to sublethal rates of dicamba, 2,4-D, or the premixed product from most susceptible to least susceptible was ageratum > alyssum > marigold (Tagetes erecta L.) > dahlia > geranium = salvia = snapdragon = impatiens. Differences in overall susceptibility to the plant growth regulator herbicides evaluated should provide useful information to horticulturalists designing annual flower beds and borders and lawn care applicators.

Free access

Raymond P. Poincelot

A seaweed/humus extract (ROOTS) was tested as a propagation biostimulant. Transplants from seed showed enhanced root, root hair, and shoot growth. Cultivars tested included: Broccoli `Bonaza', Coleus `Park's Bril1iant', Dahlia `Redskin', Eggplant `Early Bird', Gazania `Pinata', Geranium `Earliana' and `Hybrid Orbit', Impatiens `Shady Lady' and New Guinea `Tango', Marigolds `Gay Ladies' and `Climax', Nicotiana `Nikki', Pepper `Park's Whopper', Petunia `Total Madness', and Tomatoes `Sweet Million', `Good n Early', `Better Boy', `Early Girl', `Lady Luck' and `Super Steak'. Cuttings from citrus cultivars showed improved rooting (Lemon `Ponderosa', Lime `Bearss', and Orange `Calamondin'). Cuttings from succulents also showed improved propagation (Pedilanthus tithymaloides cucullatus, Senecio deflersii, and an unknown stapeliad species). Seaweed extracts, known growth stimulants, when fortified with humic acid, offer promise as a propagation biostimulant.

Free access

William B. Miller, Anil P. Ranwala, Garry Legnani, Merel Langens-Gerrits, Geert-Jan de Klerk, Johannes Eckelmann, and Michael Ernst

Ornamental geophytes comprise a large and diverse group of plants characterized by underground storage organs that serve the obvious function of reserve storage and subsequent supply during early stages of shoot growth. Relative to many agronomic and horticultural crops, the fundamental physiological bases of carbon metabolism, partitioning, and utilization in geophytes are unclear. One reason is diversity in organ morphology (bulb, corm, tuber, root, rhizome, etc.), storage carbohydrate (starch, fructan, glucomannan, etc.), and growth habit (e.g., synanthous vs. hysteranthous flowering). Knowledge of factors that control accumulation and mobilization of carbohydrate reserves may lead to manipulations that considerably improve the quality and culture of these crops. We are utilizing a variety of techniques and experimental systems to study selected internal and external controls or influences on geophyte carbohydrate metabolism and partitioning. Specific examples to be discussed include bulb storage temperature effects on starch and fructan metabolism in Tulipa, effects of carbon source and dormancy breaking treatments on starch and glucomannan metabolism in in vitro-grown Lilium bulblets, photoperiod control of fructan accumulation in Dahlia seedlings, and biochemical and molecular features of soluble and wall-bound invertases in developing Lilium longiflorum flower buds.

Free access

Fahed A. Al-Mana and Tarik M. El-Kiey

Production of five commercial cut flowers in different culture media, namelyI nutrient film technique (NFT), soilless media (perlite and an equal mix of perlite and peatmoss), and soil mix (2 sand: 1 loam by volume), was investigated in controlled fiberglass-house. Two rose varieties (Rosa hybrida var. Baccara and Madina); carnation (Dianthus caryophyllus var. William Sim); Chrysanthemum morifolium var. Delta, and Dahlia hybrida var. variabilis were used. Plants were watered as they needed by the same nutrient solution used for NFT.

Generally, growth and yield of Baccara and Madina roses, Chrysanthemum and Dhalia plants were superior in NFT than in the other media. On the contrary, the growth and yield of carnation plants were significantly greater in conventional soil or perlite and peatmoss mix than in NFT or perlite.

Flower crops grown in NFT generally reached harvest stage 5-10 days earlier than those grown in the other media except carnation plants. There were variations in the accumulation of N, P, K mg, ca, and Fe in plant leaves among the various culture media.

Open access

Cristian E. Loyola, John M. Dole, and Rebecca Dunning

respondents in Canada and the United States (n = 210). The five most common grown or handled crops were zinnia, peony, snapdragon, sunflower, and dahlia ( Table 3 ). Three of the five species, zinnia, sunflower, and snapdragon, were also among the top five