I think shipping anything within two weeks of Xmas, you're taking a chance that your package will arrived on time. Unless you're paying for overnight shipping.
Both as a customer and seller need to be bewared of the potential risks. Usually customers don't know nor care about the shipping hazard of shipping close to the holidays. Since they paid, they demanded to have their stuff ASAP. As the seller you could be waiting days to get paid for the item (customer don't care about) and once paid the seller hands are tied because you're under the mercy of the buyer demand to have their item ASAP.
If you don't do it, your customer will be angry that they don't get their asap. Some will understand the circumstances and wait. But most will not which leads to delay, lost packages, dead plants, dead fish. All equal to bad transaction and a public out cry from the buyer.