Opium poppies are specifically scheduled under U.S. Law. The Controlled Substances Act, Schedule II, lists "Opium poppy and poppy straw" as well as "Concentrate of poppy straw (the crude extract of poppy straw in either liquid, solid or powder form which contains the phenanthrene alkaloids of the opium poppy)". Opium and its constituent chemicals are listed in Schedule II and some derivatives (such as Heroin) are listed in Schedule I.

There is some confusion in the law, however, because opium-producing poppies are widely grown around the US and Canada and the opium poppy seeds are omnipresent in cooking, breads, and deserts. The grey-blue poppy seeds sold in virtually every grocery store in the US contain low levels of opiates (not psychoactive at amounts used in cooking). Poppy pods are widely used in dry flower arrangements. Poppy seeds are specifically excluded from the controlled substances act, but in 2019, the DEA issued a statement saying that they considered poppy seeds that have not had the opium removed to be controlled. See https://www.deadiversion.usdoj.gov/drug_chem_info/unwashed_poppy_seed.pdf

Law enforcement in the US is somewhat inconsistent about these plants, although there are continual attempts to try to stop them from being sold or grown. If poppies are grown as sources for opiates, there is no question that it violates the CSA. If poppies are purely grown for ornamental purposes, their legal position is somewhat less clear cut, since they are so widely grown and available.

Opium for legal commercial pharmaceutical use is grown with special government licenses around the world, although very little of it is grown inside the US. Large scale underground opium poppy growing is reported to take place in Mexico, Afghanistan, and many other countries in Asia. Much of the produced opium is converted into heroin because it is easier to ship and commands a higher price than raw opium.

The U.S. DEA recently re-affirmed in 2006 that Afghanistan is not a legal source for poppy products. See http://a257.g.akamaitech.net/7/257/2422/01jan20061800/edocket.access.gpo.gov/2006/E6-16325.htm:

  (f) Notwithstanding paragraphs (a)(1) and (a)(2) of this section, 
the Administrator shall permit, pursuant to 21 U.S.C. 952(a)(1) or 
(a)(2)(A), the importation of approved narcotic raw material (opium, 
poppy straw and concentrate of poppy straw) having as its source:
    (1) Turkey,
    (2) India,
    (3) Spain,
    (4) France,
    (5) Poland,
    (6) Hungary, and
    (7) Australia.
    (g) At least eighty (80) percent of the narcotic raw material 
imported into the United States shall have as its original source 
Turkey and India. Except under conditions of insufficient supplies of 
narcotic raw materials, not more than twenty (20) percent of the 
narcotic raw material imported into the United States annually shall 
have as its source Spain, France, Poland, Hungary and Australia.