Dirca palustris, and its diminutive flower

yellow flowering shrub

Dirca palustris, or Leatherwood, is found in the Thymelacaceae family.

Dirca palustris, commonly called Leatherwood or Eastern Leatherwood, is found in the Thymelaeaceae family.  This sweet little native Missouri deciduous shrub is blooming right now right outside of the Tucker greenhouse.  It typically blooms from March to April, but the flowers are so tiny, one could easily miss them blooming in the woods.  The flowers are pale yellow and about a centimeter long. This sweet little shrub prefers to grow in part shade to full shade.  It blooms before the leaves emerge.  After the flowers are pollinated, they produce a green drupe fruit (fleshy fruit with one seed).

The genus name comes from the Greek word for fountain.  The species name means ‘marsh-loving’. This plant does prefer a moist habitat near streams, or rich bottomland.

Trialeurodes vaporariorum, better known as ‘those nasty whiteflies’


Ficus leaves damaged by whiteflies

The Tucker Greenhouse has its share of ‘critters’, but right now there is a ‘bloom’ of these nasty whitefly insects, AND they are slowly defoliating a large Ficus tree in one of the tropical greenhouses. They seem to like certain plants better than others too.  They love feeding on members of the Araceae, and Moraceae plant families in particular.

For a great description of whiteflies and the havoc they can wreak on plants, see the following from Planet Natural, a research center for organic gardeners…

 “Common on houseplants and in greenhouses, the whitefly (Trialeurodes vaporariorum) is a sap-sucking insect that is often found in thick crowds on the undersides of leaves. When infested plants are disturbed, great clouds of the winged adults fly into the air. Both nymphs and adults damage plants by sucking the juices from new growth causing stunted growth, leaf yellowing and reduced yields. Plants become weak and susceptible to disease. Like aphids, whiteflies secrete honeydew, so leaves maybe sticky or covered with a black sooty mold. They are also responsible for transmitting several plant viruses. 
Adults (1/16 inch long) are moth-like insects with powdery white wings and short antenna. They are easily recognized and often found near the tops of plants or on stem ends. Wingless nymphs are flattened, oval and almost scale-like in appearance. After the first instar, or crawler stage, they settle down and attach themselves to the underside of leaves and begin feeding.
Young nymphs overwinter on the leaves of host plants. In late spring adult females deposit 200-400 eggs in circular clusters on the undersides of upper leaves. The eggs hatch in 5-10 days and first instar nymphs, which resemble small mealybugs and are called crawlers, move a short distance from the egg before flattening themselves against the leaf to feed. The remaining nymphal stages (2nd, 3rd and 4th) do not move. A non-feeding pupal stage follows and within a week, young adults emerge to repeat the cycle. There are many generations per year. Whiteflies develop from egg to adult in approximately 25 days at room temperature. Adults may live for one to two months.”
Since the Tucker Greenhouse is filled with a diverse group of plants, and since people of all age groups walk through it on a daily basis, I try and limit the use of harmful pesticides.  I do use insecticidal soap, and an occasional systemic insecticide applied to soil, but largely, I depend on beneficial insects to help me combat the vast array of plant feeding insects that visit the greenhouse regularly.  I use lady bugs, mealybug destroyers, and whitefly parasitic wasps.
Today I received a package in the mail of 3,000 Encarsia formosa pupae.  Encarsia is a whitefly parasitic wasp that feeds on whiteflies.
The package of 3,000 pupae was shipped on ice to keep the insects cool during shipment.  So, since these tiny, delicate wasp pupae are one these cards, I’ll be placing them on the branches of plants throughout the tropical room.  Stay tuned for the results!

Curry Leaf, or Curry Tree

white flower

Murraya koenigii, commonly called Curry Leaf, is found in the Rutaceae (Citrus) family.

The Curry Tree or Curry Leaf plant is very fragrant.  The flowers are fragrant, the leaves are fragrant, the whole plant is simply fragrant!  This tropical plant is native to the moist forests of south Asia. The fresh leaves of the plant are used as a flavoring in Indian/Asian cuisine.

For more information on the use of the Curry Leaf plant please check out http://kurma.net/essays/e8.html

The Tucker Greenhouse Curry Leaf plant is located in the main hallway at the entrance to the greenhouse. When you find it, feel free to gently pull off a small leaf and crush it in your hands, or simply smell the flowers. The aroma is tantalizing.  If these flowers produce seeds, I’ll be planting them a.s.a.p.

The genus name Murraya, pays honor to Johann Andreas Murray, a Swedish professor of medicine and botany in the 1700’s.