Volume 17(2), 9- 12, 2013 JOURNAL of Horticulture, Forestry and Biotechnology www.journal-hfb.usab-tm.ro

Species of acclimatization in the Botanical Garden of Jibou and their promotion in landscape

Căprar M.1 *, Maria Cantor 2, C. Sicora 1

1) Biological Research Center, Botanical Garden “Vasile Fati”Jibou, Parcului Street, no.14, 455200 Jibou, Romania; 2) University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca, Faculty of Horticulture, Manastur Street, no 3-5, 4000472 Cluj-Napoca, Romania

*Corresponding author. Email:[email protected]

Abstract The current paper presents the preliminary results of a study Key words regarding the behaviour in crop condition of four Rhododendron , from different parts of the world (Europe, China, Korea, USA) with ornamental Rhododendron sp., value. The research initiated in the Botanical Garden Jibou will help the ornamental value, selection and propagation of ornamental representatives of species that are adaptability, characteristics tolerant to low temperatures, suitable for cultivation in Northwestern Romania.

In the present context, the major problems of flower lovers can enjoy the beauty of these in contemporary civilization are the protection, their gardens [4]. preservation and improvement of the environment. It is Once successfully cultivation of essential to stimulate interest in bringing nature, and are without equal in especially woody vegetation - with its immense landscape design. Evergreen forms are beautiful all services that often are ignored, into our living year round. Deciduous azaleas have very beautiful environment, improving climate and the urban foliage in autumn, offering some of the most brilliant environment and the irreplaceable beauty that trees and colors of yellow and orange. Planted in groups, they bring to the human habitat. eclipse any ornamental in the landscape with Rhododendron genus includes shrubs of great their beauty [1]. beauty and elegance of flourishing, species and The results obtained from the investigations obtained by hybridization in large number can help promote Rhododendron species that are including azaleas. Aptly named “ornamental shrubs adapted to environmental conditions in the area, kings" [5], with a spread on four continents, a whole resistant to low temperatures and that withstand the industry has grown around them in the recent years. It heat of summer. developed an entire branch of production and Within Jibou Botanical Garden, species of marketing of horticultural ornamental woody plants. Rhododendron that adapt to local conditions are Unfortunately, in Romania there is currently no multiplied in nurseries and are promoted for rhododendron breeding ground specialized in arrangement of green spaces. Further improvements are production at a professional level although the demand made to growing and breeding technologies for the exists for this variety. Most plants that exist in our production of quality seedlings in a large variety of country are imported and often they are not adapted to species and cultivars, better adapted to climatic face climate in Romania which leads high losses in the conditions in our country. first year after planting. Rhododendrons and azaleas are more Materials and Methods demanding in growing requirements than many commonly cultivated plants and thus will not grow The study was conducted during 2010-2012 using 4 easily in any garden. Rhododendron is a very diverse species of rhododendron (Rhododendron poukhanense, genus with over 1100 species which vegetate naturally Rhododendron luteum, Rhododendron sutchuenense, in very different areas, from the tropics to the high Rhododendron catawbiense) who were chosen mountain area, but with some changes to the ground especially for resistance to frost and for their and the correct choice of species and cultivars, most ornamental value and proven adaptability during 2002 - 2012 (Fig. 1.), [1].

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a) Rhododendron catawbiense b) Rhododendron luteum

c) Rhododendron sutchuenense d) Rhododendron poukhanense

Fig. 1. (a-d). Rhododendron species studied in 2010-2012

The biological material used in the first time in Romania and tested in climatic conditions experiments comes from the collection of at Jibou Botanical Garden [2]. rhododendrons of the Botanical Garden Jibou. Since All species of Rhododendron chosen as 1998, within the international trade of seeds, began the biological material proposed for study are plants aged acquisition of seeds from species of rhododendron, 10-12 years, depending on the species with heights up which according to the literature, would be resistant to to 170 cm, which blossom and fructify each year and both low and high temperatures and low relative last great in the weather conditions here. humidity. Many of these species were brought for the

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The experimental field where observations phenological observations on the species of were made is an area of land, near the research Rhododendron (Fig. 2). The place was chosen also laboratories, where it was tested in particular the because of the protection offered by the shades of capacity to adapt to climate conditions and many trees planted in the area.

Fig. 2. General view of experimental field

For each specie is synthesized information height in 10 years flower color, bio-form and regarding the morphological characters of the , geographic distribution (Table 1), [4].

Table 1 The biological material used in experiments Geographic Height in 10 Flower Species Bio-form Comments No. distribution years (m) color Phanerophyt Rhododendron poukhanense Korea 0.5-1.2 lilac Evergreen - 1. H.Lev. subshrub From Eastern Phanerophyt Rhododendron luteum Flowers Europe to the 1.5-2 yellow Deciduous 2. (Linnaeus) Sweet fragrant Caucaz shrubs Rhododendron sutchuenense lilac to Phanerophyt Western China 1.5-2 - 3. Franchet rose Evergreen shrub Widely 4. Rhododendron catawbiense Eastern United lilac to Phanerophyt 2-3 adapted Michaux States pink Evergreen shrub plant

Results and Discussions Table 2 were presented the results regarding the behavior of plants in crop conditions, appreciated The decorative aspect at all the four species through recorded biometric measurements. Evaluation studies is assured, mainly by the flowers with different and monitoring of morphological characters were colors, completed by the leaves and the elegance of realized during the vegetation period. plant port. The ones that had normal growing and development like in the natural habitat conditions. In

11 Table 2 Phenological and morphological observations of Rhododendron sp., 2010-2012 Height in Flowering Floral bud experimenta Growing season numbers Decorative Species l field after and No. (decade/ part 10 years (m) development month) 2010 2011 2012 2012 Rhododendron 1. III/04 0.8 38 46 58 Fl normal poukhanense H.Lev. Rhododendron luteum 2. III/05 1.7 57 68 87 Fl, L normal (Linnaeus) Sweet Rhododendron 3. I/06 1.7 87 102 124 Fl, L normal sutchuenense Franchet Rhododendron 4. II/05 1.8 57 89 98 Fl, L normal catawbiense Michaux Fl - flowers color, L- leaves In all of the four species studied were year to year, all four species ranging from 38 to 124. observed that the increase in height, in 10 years is All four species were not affected by cold in three normally falling within the range reported in other years observations, although negative temperatures of - specialty papers [4]. The fact that all blossom and 23 C were recorded. In terms of rainfall they were fructify and they look like they have viable seeds show supplemented by irrigation because three years have that they are adapted to environmental conditions of been quite drought (Table 3). During the experiment the area and can be promoted for setting up parks and there were no reported attacks by pests and diseases. gardens. The number of flower buds is increasing from

Table 3 Absolute monthly minimum temperature ( C) and the atmospheric precipitations (mm/m2) recorded in 2002-2011/Meteorological Station of Jibou

Absolute monthly minimum temperature The atmospheric precipitations (mm/m2) ( C) Year January February December Multiannual average 2010 -11.2 -7.5 -7.1 497.2 2011 -23.0 -16 -14.8 228.4 2012 -14 -10 -12.4 325.7

Conclusions References At the species Rhododendron poukhanense, 1. Băla Maria, 2012, Floricultură generală şi specială. Rhododendron luteum, Rhododendron sutchuenense, Ed. Partos Timişoara, p.360. Rhododendron catawbiense the main decorative 2. Căprar M., Cantor Maria, Sicora C., 2011, element is represented by flowers and leaves. These Behaviour of Rhododendron species to low and negative decorative characteristics justify the recommendation temperature in the Botanical Garden Jibou in 2002- of the studied species for crop using in ornamental 2010, Bulletin USAMV Horticulture, 68(1): 309-314. purposes. The studied species cover almost the same 3. Cullen J., 2005, Hardy Rhododendron species a decorative period as in natural habitat, decorating guide to identification, Timber press. through flowers from April to June and leaves from 4. Douglas G., David C., Argent G., 2011, The red list April to September. of Rhododendrons, p. 7-10. All four Rhododendron species can be used in 5. Reiley H. E., 2004, Success with rhododendrons and future breeding program as parents for hybridizing and azaleas. TimberPress, Portland. promotion in landscape design under temperate climate.

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