Growth, Flowering, and Cold Hardiness of Rockrose in Western Oregon

Abstract

<jats:p>Ninety-three species, cultivars, and hybrid selections of rockrose (<jats:italic>Cistus</jats:italic> spp., <jats:italic>Halimium</jats:italic> spp., and ×<jats:italic>Halimiocistus</jats:italic> spp.) were evaluated for growth, flowering, and cold hardiness in a landscape trial in Aurora, OR, from 2004 to 2009. Plants were irrigated to aid establishment when planted in summer 2004, but thereafter were not watered, fertilized, or pruned throughout the trial. Cold damage was recorded following freezing events in Feb. 2006 and Dec. 2008 in which low temperatures were 20 and 17 °F, respectively. Those plants that consistently suffered the most cold damage were <jats:italic>Halimium atriplicifolium</jats:italic>, <jats:italic>Cistus creticus</jats:italic> ssp. <jats:italic>creticus</jats:italic> ‘Tania Compton’, <jats:italic>Cistus</jats:italic> ×<jats:italic>pauranthus</jats:italic>, and <jats:italic>Cistus albidus</jats:italic> forma <jats:italic>albus</jats:italic>. Other plants showed cold damage related to poor vigor. The length of the flowering period and foliage quality varied widely among plants in the evaluation. The plants with the longest flowering period were <jats:italic>Halimium</jats:italic> ×<jats:italic>pauanum</jats:italic>, <jats:italic>Cistus inflatus</jats:italic>, <jats:italic>Cistus</jats:italic> ×<jats:italic>pulverulentus</jats:italic> ‘Sunset’, and ×<jats:italic>Halimiocistus</jats:italic> ‘Ingwersenii’, all of which flowered for more than 55 days. Plant form and foliage quality declined drastically for some plants during the evaluation. Those that retained the best foliage quality included <jats:italic>Cistus</jats:italic> ×<jats:italic>obtusifolius</jats:italic>, <jats:italic>Cistus</jats:italic> ×<jats:italic>laxus</jats:italic>, C<jats:italic>istus salviifolius</jats:italic> ‘Gold Star’, <jats:italic>Cistus</jats:italic> ‘Gordon Cooper’, <jats:italic>Halimium lasianthum</jats:italic> ‘Sandling’, <jats:italic>Halimium</jats:italic> ‘Susan’, and ×<jats:italic>Halimiocistus sahucii</jats:italic>. Based on ratings of foliage and bloom time, as well as hardiness, several <jats:italic>Cistus</jats:italic> are recommended as drought-tolerant groundcovers, including <jats:italic>Cistus</jats:italic> ×<jats:italic>gardianus</jats:italic> and <jats:italic>C</jats:italic>. ×<jats:italic>obtusifolius. Cistus</jats:italic> ×<jats:italic>laxus</jats:italic>, <jats:italic>C. inflatus</jats:italic>, <jats:italic>Cistus</jats:italic> ‘Gordon Cooper’, <jats:italic>Cistus</jats:italic> ‘Ruby Cluster’, and <jats:italic>Cistus</jats:italic> ‘Snow Fire’ are suggested as tall groundcovers or landscape specimens. Several <jats:italic>Halimium</jats:italic> are recommended for landscape use, including <jats:italic>H. lasianthum</jats:italic> ‘Sandling’, <jats:italic>Halimium</jats:italic> ‘Susan’, <jats:italic>H</jats:italic>. ×<jats:italic>pauanum</jats:italic>, and ×<jats:italic>Halimiocistus</jats:italic> ‘Ingwersenii’.</jats:p>

Cold Hardiness of Grevillea in Western Oregon

“…Injury to specific cultivars varied between the two cold spells evaluated in this study; in some cases, they varied considerably. This was seen to some extent in previous landscape studies of woody plants (Bell, 2009;Bell and Altland 2010). Although there is considerable literature about the variations in the cold hardiness of woody plants between seasons within a given year, no work has addressed the causes of variation in hardiness of individual plants between growing seasons.…”

Comparative study on hydrolysis and bioethanol production from cardoon and rockrose pretreated by dilute acid hydrolysis

“…Cynara cardunculus (cardoon) and Cistus ladanifer (rockrose) are examples of such plants, which can be used entirely or just part of them for this purpose (Fernandes et al, 2015;Ferro et al, 2015;Pesce et al, 2017;Rettenmaier et al, 2015). Cardoon and rockrose are perennial plants well adapted to the Mediterranean climate with low requirements of irrigation and fertilizers for cultivation between other crops (Bell and Altland, 2010;Fernández et al, 2006). In many regions, these are considered as invasive low economic value plants and make forest tracts vulnerable to the outbreak emergence and spread of fire (Nunes et al, 2005).…”