The certificate and the quarantine review happen before any carrier gets involved, and no carrier can skip either one for you.
Why this is agriculture law, not shipping
USPS states the rule directly in its International Mail Manual: “Plants, seeds, and plant materials, including fruits and vegetables, are subject to the provisions of Publication 52, chapter 5; Publication 14, Prohibitions and Restrictions on Mailing Animals, Plants, and Related Products; and the quarantine regulations of the country of destination.” USPS, International Mail Manual section 138, pe.usps.com, read 2026-08-30.
Two separate authorities sit behind that one sentence. The United States decides whether a plant may leave the country at all, through the same Plant Protection Act framework that governs mailing plants domestically. The destination country then runs its own quarantine review on the way in, entirely independent of anything the US decides. USPS's own international shipping guidance is blunt about the practical effect: perishable items, including plants, must be packaged and sent so they arrive before they deteriorate, they travel at the mailer's own risk, and “each country has its own rules on what it will and won't allow” — checked against that country's Individual Country Listing, not against a single federal rule that covers every destination the same way. USPS, International Shipping Restrictions, usps.com, read 2026-08-30.
The document most destinations actually require
The US Department of Agriculture's Animal and Plant Health Inspection Service issues the certificate that clears this hurdle. APHIS states what the document is for: a phytosanitary certificate “attests that the products are free from pests and diseases of concern,” and exporters need one to meet the destination country's own entry requirements. APHIS, Plant and Plant Product Exports, aphis.usda.gov, read 2026-08-30.
Getting one
APHIS names the process on its certification page. A shipper contacts their state's export certification specialist, who works with an APHIS-authorized certifier, the role APHIS abbreviates to ACO, to inspect the flowers and file the application through the Phytosanitary Certificate Issuance and Tracking system; an approved certificate is available immediately online to download and print. A standard certificate covers plants of US origin, inspected and found free of certain pests and conforming to the destination's regulations; a separate Certificate of Reexport exists for foreign-origin plant material that already entered the US under its own valid certificate and “has not been subjected to the risk of infestation during storage.” A user fee applies to either one, and APHIS notes that the amount “vary[ies] based on the Federal, State, or county authority conducting the inspection.” APHIS, Plant and Plant Product Export Certificates, aphis.usda.gov, read 2026-08-30.
None of that is optional paperwork layered on top of a shipping label. A parcel without the certificate the destination requires does not clear that country's border, no matter which carrier is carrying it or how it was packed.
The honest answer for most occasions
Cut flowers barely tolerate a day out of water inside the same country. Our own guide to shipping flowers domestically treats overnight air as the sensible default for that reason alone, with ground usable only in genuinely cool weather over a short zone and no border to cross. Add a phytosanitary inspection, a certificate that takes time to arrange, a customs entry at the far end and a destination quarantine review, and the flowers are very often dead before the paperwork clears.
A local florist skips the whole problem
A florist physically located in the destination country, arranged through a wire service, never crosses a border at all. No certificate, no customs entry, no quarantine review — because nothing agricultural ever left its own country.
Save international for the exception
A grower or a business shipping stock in volume, on a schedule, with a certificate already arranged, is a different case from a one-off gift. For a single bouquet, the certificate cost and the transit risk rarely make sense against what it is buying.
Silk, dried or preserved sidesteps agriculture law
A non-living arrangement is not plant material in the sense these rules cover, so it skips the phytosanitary question entirely. It still has to clear the destination's ordinary customs process like any other parcel.
If the trip is domestic instead
None of the certificate or quarantine material above applies inside the United States. Our guide to shipping cut flowers covers the packing, the cold pack, the box shape and the overnight service choice for a domestic bouquet, and SMKlog's checkout prices that leg with a live carrier quote. A gift crossing a border is the case this page is about; a gift staying inside the country is a packing problem, not a plant-health one.
Where these rules come from
- USPS, International Mail Manual, section 138 — perishable matter, plants subject to Publication 52, Publication 14 and destination quarantine rules. Read 2026-08-30.
- USPS, International Shipping Restrictions — perishable packaging obligation, shipment at mailer's risk, and the Individual Country Listings. Read 2026-08-30.
- APHIS, Plant and Plant Product Exports — what a phytosanitary certificate attests and why exporters need one. Read 2026-08-30.
- APHIS, Plant and Plant Product Export Certificates — the standard certificate, the Certificate of Reexport, the application process through a state export specialist and PCIT, and the user fee. Read 2026-08-30.
Destination-country requirements are set by that country and can change without notice to any of the pages above. Confirm the current rule for the specific destination through APHIS's Phytosanitary Export Database before shipping.
International flower shipping questions
Can I mail cut flowers to another country?
Sometimes, but a plant-health rule decides it before any carrier rule does. USPS's International Mail Manual states that plants, seeds and plant materials are subject to federal mailability rules and the quarantine regulations of the country of destination, and most destinations require a phytosanitary certificate from APHIS before cut flowers can cross their border at all.
What is a phytosanitary certificate?
A certificate the US Department of Agriculture's Animal and Plant Health Inspection Service issues to attest that plants or plant products are free from pests and diseases of concern, so a shipment meets the destination country's entry requirements. Without one, most countries will not admit cut flowers or live plants at all.
How do I get a phytosanitary certificate?
Through your state's APHIS export certification specialist, who works with an APHIS-authorized certifier, the role APHIS abbreviates to ACO, to inspect the shipment and file the application through the Phytosanitary Certificate Issuance and Tracking system. A user fee applies, and it varies by which federal, state or county authority does the inspection.
Is it actually worth shipping flowers internationally myself?
Usually not, and it is worth saying outright. Cut flowers tolerate almost no delay even inside the US, and an international shipment adds a certificate, a customs entry and a destination quarantine review on top of the transit time. A local florist in the destination country, arranged through a wire service, skips all of it because nothing crosses a border.
Does SMKlog ship flowers internationally?
No. Plants and plant material sit on our shipping restrictions list, and this checkout does not produce the phytosanitary paperwork above; the international labels it does sell, to Canada, the UK, Germany and Australia, are for ordinary goods. For domestic flower shipments, our guide to shipping cut flowers covers the packing, the cold pack and the service choice.