Managing Landscape Palms Linda Seals agente de extensión agricola el condado de Brevard, Florida Parts of this presentation were adapted from a presentation created by Kim Gabel, Horticulture Extension Agent, Monroe County UF-IFAS Extension. Managing Landscape Palms

Palm Anatomy Monocot Palmate, costapalmate, or pinnate fronds One central growing point - bud

Palm Stem Vascular bundles concentrated to outside of stem (decreasing towards the center). Relative distribution of vascular bundles between inner and outer regions varies between species.

woody trunk vs. palm stem

Palm Stem Stem surface varies among species Phoenix (knobby) vs. Cocos (smooth) All palms with a crownshaft are self-cleaning Roystonea, Hyophorbe, Adonidia merrillii, Wodyetia bifurcata, Dypsis sp. Other palms may or may not be self-cleaning Phoenix spp., Sabal spp., Washingtonia spp., Syagrus spp., Livistonia spp. Cannot determine age of palm based on stem height or diameter

Palm Leaves Number of leaves produced is function of species and environment, especially nutrition. In general, for every visible leaf, equal number of leaves in development in bud (heart = apical meristem) Damage to bud affects leaves that will emerge later

Longitudinal cross-section through bud

Right palm, right place Palm height Growth rate Hardiness Zone Salt tolerance Light requirements Nutritional needs Human hazards Major Pest problems Major Disease or Physiological problems

Environmental Effects Light Water Wind Lightning Powerline Decline Herbicides

Parlor Palm Chamaedorea elegans Light Palms growing in full sun require higher fertilization rates than shade grown palms in order to maintain dark green color and growth rate. Parlor Palm Chamaedorea elegans Sunburn: large necrotic areas on upper leaf surface

Water Prolonged drought causes growth reduction, leaf desiccation, starting with leaf spear. Poor drainage causes wilting and poor growth. Most established in ground palms are drought resistant. Geonoma sp. Cocos nucifera

Salty Water quality problems Water soluble fertilizers or saltwater intrusion. Foliage appears wilted, leaf tip necrosis, especially old fronds. Salt damage can injure root tips.

Salt Spray Wind Damage Extensive necrosis, rinse foliage with fresh water Salt wind tolerant palms: Allagoptera arenaria Coccothrinax spp. Cocos nucifera Hyophorbe spp. Pseudophoenix spp. Serenoa repens Thrinax spp.

Hurricane Wind Damage

Lightening Fatal - sudden collapse of the crown Longitudinal splitting or dark color streaks on the trunk Trunk bleeding from breaks or spots scattered throughout trunk Protection of valuable palms with lightning grounds

Powerline Decline Palm fronds within 1 to 2 feet of powerlines exhibit yellow tip and dieback. Prevention: do not plant tall growing palms directly under or close to overhead lines

Herbicides Arrested development of new leaves, when leaflet emerges show necrotic blotches, tip necrosis “accordion leaf” and stunting Symptoms may not become visible until 7 to 9 months after application Roystonea regia (Cuban Royal Palm)

pH Alkaline soils occurs where soils or the fill is derived from parent material high in limestone, such as the shell and/or coral rock Alkaline soils "tie up“ essential nutrients making them unavailable

Common Landscape Deficiencies Turfgrass: Nitrogen, Iron Broadleaf plants: Magnesium, Iron, Manganese, Potassium, Nitrogen Palms & other monocots: Potassium, Magnesium, Manganese, Boron, Nitrogen, Iron Turfgrass and broadleaf plants are susceptible to some of the same nutrient elements as palms in Florida landscapes. Thus, any fertilizer that provides sufficient nutrients for palms will also provide sufficient nutrients for turfgrass and broadleaf plants

Potassium (K) Deficiency Most important limiting element in palms Translucent yellow-orange or necrotic spotting of foliage Marginal and/or leaflet tip necrosis Most severe on oldest leaves and towards tips of affected leaves Potassium deficiency is by far the most important limiting element in palms grown in the field or landscape, not only in Florida, but throughout the palm-growing world. It was only in 1988 that we determined the identity of this ubiquitous problem in landscape palms. Symptoms are quite variable, being affected by the species, and by the severity of the deficiency.