Monday, December 15, 2014

Hapuu, the Hawaiian Tree Fern, vs. the Australian Tree Fern



                                                        
The Hawaiian tree fern is native to most of the Hawaiian Islands. Although once common, hapu’u stands have been reduced due to a large number of ferns being harvested for orchid media and landscape use. The last remaining large stands of native hapu’u are found on the Big Island.

The Hawaiian hapu’u  are very slow growing; the young ones grow at about 3.5 inches per year while the older plants grow even more slowly, eventually growing to  15-20 feet tall.  The unfurled fronds are covered with silky, red-brown wool-like fibers called pulu.  In the past, pulu was used for stuffing pillows and mattresses and for dressing wounds.




The Hawaiian tree ferns are relatively easy to grow. They grow best in well drained slightly acid soils and partial shade; they will tolerate full sun in cloudy upland areas. They need a steady supply of water and occasional light applications of a complete, slow release fertilizer. Old and injured fronds should be pruned. It is illegal to ship tree ferns or products from the ferns internationally. 


 The Australian tree fern, Cyathea cooperi, is considered invasive in the State of Hawaii due to aggressively out competing native plants in the forest understory. As a threat to  Hawaiian forests, this fern eventually displaces the native ferns, including the slower growing Hawaiian tree fern, or hapu’u.  


Although invasive, the Australian tree fern is being sold in Hawaii at many commercial plant nurseries. This fern grows to 40 feet tall and tolerates full sun in cool wet areas. The spores are spread by wind and can travel over 7 miles from the parent plant.

 The best diagnostic characteristic to distinguish between the Australian tree fern and the native hapu'u is the hairs on the leaf stems. With the  hapu’u, the hairs are either fine and reddish-brown for hapu'u pulu (Cibotium glaucum) or fine and black for hapu'u i'i (C. menziesii). The hairs on the Australian tree fern are broad and white.
     



                                                Cibotium menziessi

  Photos: Native Plants Hawaii, University of Hawaii












 

Monday, December 8, 2014

Propagation of Blueberries



Blueberries are propagated from either softwood or hardwood cuttings.  

Hardwood cuttings are collected in late January or February, after sufficient chilling has occurred. Follow these simple directions: collect shoots from the previous summer, 12 to 36 inches in length. Select healthy material, avoid propagating from plants that have odd-looking or stunted foliage. Divide the shoots into pieces 5 to 6 inches long, removing any flower buds. Place cuttings in a propagation bed at a depth of one-half to two-thirds of their length. Finally, keep moist.


Softwood cuttings are taken in late spring from the current season's growth, 4 to 5 inches long. Here are the directions: collect these cuttings when the stems have developed woody tissue but are still somewhat flexible. Remove all leaves with the exception of two or three terminal leaves.  Place cuttings in the propagation bed, under mist at a depth of one-half to two-thirds of their length.

Rooted cuttings are eventually transplanted into pots and held for about one year.  During the time of rooting, keep beds moist while being aware not to over water.
For the propagation process, a greenhouse is not necessary, but some type of propagation bed/chamber, under 40 to 70 percent shade with a mist system is recommended; an area as small as 3x3x3 can be used.
The mist system should keep the media uniformly moist but not soggy.  An intermittent-mist system with frequent, short misting intervals is recommended in order to keep the humidity near 100 percent.  However, keeping the cuttings at this constant moisture also creates an ideal environment for pathogenic fungi to grow. Thus cleanliness is very important; use new or sterilized planting mix and pots, keeping them raised off the ground.
  
Potting media containing various mixtures of coarse sand, ground pine bark, perlite, sawdust, and peat moss have proven satisfactory. According to a publication from the University of Hawaii, a good rooting medium recipe is a mixtures of coarse sand, ground pine bark, and peat moss at 1:1:1, or perlite and peat moss at 1:1.



Monday, December 1, 2014

Spittlebugs



Are your plants foaming at the leaves?

A white frothy substance on plants may be a spittlebug. Inside all that froth is a tiny bug about ¼ - ½ inch long.  The immature stage of this insect sucks the plant juices just as aphids do. But in the process, spittlebugs remove so much water and carbohydrates, that excess fluid is produced. They then cover themselves with this fluid. The spittle is produced when the insect bubbles air from the tip of the abdomen into the liquid. This is an ingenious method to protect themselves from predators and  from drying out.

Although the removal the plant fluids can weaken the plant, rarely are spittlebugs a serious problem. Simply spraying a strong stream of water can physically remove the pest. A soap/oil spray can also be used.

In addition to basil, the spittlebug attacks other common plants such as rosemary, mint, hibiscus and some pine trees.