The cedarwood essential oils from Texas and Virginia can be very similar, but there are different claims and different processing for each of the oils.
From Leung's Encyclopedia of Common Natural Ingredients (click here for the excerpt): Cedarwood oil Virginia contains mainly α-and β-cedrene (ca. 80%), cedrol (3–14%), and cedrenol. Other sesquiterpenes present include thujopsene, β-elemene, caryophyllene, cuparene, α-acoradiene ("acorene"), and others. Monoterpenes are also present (mostly sabinene and sabinyl acetate). Cedarwood oil Texas contains similar major constituents as cedarwood oil Virginia. Both types of cedarwood essential oil will annoy snakes. Both are considered phototoxic (although I can't find any references to this except for p. 567 in the Handbook of Essential Oils).
CEDARWOOD TEXAS (Juniperus ashei)
Texas cedarwood is steam distilled from trees that are felled specifically to create the essential oil (3, p. 76). It is further rectified to remove the orangey-brown colour to make it a nice yellow-y colour and to remove some of the stronger scents. It is considered to be an anti-spasmodic, antiseptic, astringent, and expectorant.
CEDARWOOD VIRGINIA (Juniperus virginiania)
Virginia cedarwood is steam distilled from branches, stumps, saw dust, and waste wood from trees felled primarily for making furniture. It is reported to be an abortifacient, antiseborrheic, antiseptic, antispasmodic, astringent, expectorant, and an insecticide. It is reported that cedarwood Virginia can cause skin irritation in some sensitive individuals (click here & search for cedarwood) and shouldn't be used by pregnant woman as it has a reputation as an abortifacient.
Although the government notes in this report that "Historically, nineteenth century medical compendiums contain several reports of abortion and death in humans after oral consumption of relatively large amounts of cedarwood oil..." it goes on to note that that "Although cedarwood oil has been described as a powerful abortifacient, very little data on the toxicity of any of the three cedarwood oils was found in a review of the available literature." I think it wise for pregnant and nursing women to be careful with anything they might use, and I think it wise not to drink a large amount of cedarwood oil as well.
Cedarwood Virginia is reported to be a good insecticide, and people have traditionally used cedar as a way of repelling moths. It's used in moth proofing and to preserve cloth from moths and beetles (3, p. 885). It is suggested that adding "4–5 drops of cedarwood oil and pine oil is added to a bowl of warm water and a bristle hair brush is soaked with this solution to brush the pet down with it. Eggs and parasites gathered in the brush are rinsed out. This is repeated several times. This solution can be used similarly for livestock after adding citronella and lemon grass oils to this mixture. (3, p. 884).
Join me tomorrow as we take a look at the science of a few of the compounds we find in cedarwood Texas and Virginia essentials oils!
(1) Leung's Encyclopedia of Common Natural Ingredients
(2) The Encyclopedia of Essential Oils (1992) by Julia Lawless
(3) Handbook of Essential Oils: Science, Technology & Applications - Husnu Can Baser & Buchbauer (eds).