Your friend told you wrong. You happened to get through, is all. My guess is half of you have travel have gotten by with getting cuban cigars into the US as well - same thing, except cuban cigars don't pose a potential threat to the agricultural foundation of the country. If customs catches you, you're going to be in for a very, very bad day.
The ONLY legal way to bring viable foreign plant material in is via the USDA permitting system previously described.
Edit:
http://www.aphis.usda.gov/plant_health/permits/plantproducts.shtml
any individual can get a permit. it doesn't cost anything. You'll need a level 2-USDA account, which you can also get. Karen Brady at USDA is very helpful to walk you through the process, but she's very difficult to get in person. Her contact info is on the USDA website, and most permit applications themselves.
From CBP (Customs and Boarder Patrol - enforcement):
Bringing Agricultural Products Into the United States
(02/29/2012)
If youve had food, plants or souvenirs taken away by an inspector at an international airport, border crossing, or seaport, we want to be sure you understand why.
Certain items brought into the United States from foreign countries are restricted according to U.S. Department of Agriculture (USDA) regulations. Prohibited agricultural items can harbor foreign animal and plant pests and diseases that could seriously damage Americas crops, livestock, pets, and the environment and a large sector of our countrys economy.
All travelers entering the United States are required to DECLARE any meats, fruits, vegetables, plants, seeds, animals, and plant and animal products (including soup or soup products) they may be carrying. The declaration must cover all items carried in checked baggage, carry-on luggage, or in a vehicle.
Upon examination of plants, animal products, and associated items, U.S. Customs and Border Protection (CBP) agriculture specialists at the ports of entry will determine if these items meet the entry requirements of the United States.
Even though an item may be listed as permitted from a particular country, it is always best to DECLARE the item by checking Yes on Question 11 of the CBP Declaration Form 6059B. Also declare if you have been on a farm or in close proximity of livestock, as an agriculture specialist may need to check your shoes or luggage for traces of soil that could harbor foreign animal diseases such as foot-and-mouth.
Avoid Fines and Delays
Prohibited items that are not declared by passengers are confiscated and disposed of by CBP agriculture specialists. But thats not all. Civil penalties may be assessed for violations and may range up to $1,000 for a first-time offense. Depending on whether the confiscated, undeclared items are intentionally concealed, or determined to be for commercial use, civil penalties may be assessed as high as $50,000 for individuals. The same fines apply to prohibited agricultural products sent through the international mail.
Fruits, Vegetables, and Plants
Depending on the country of origin, some fruits, vegetables, and plants may be brought into the United States without advance permission, provided they are declared, inspected, and found free of pests. However, certain plants and ANY plant parts intended for growing (propagative) require a foreign phytosanitary certificate in advance. For information on certificates, contact the USDA/APHIS Plant Protection and Quarantine Permit Unit at (301) 851-2046 or (877) 770-5990 . Also, check the Information Resources section at the end of this notice for details.
Brad.
Though you could always ask around the community to see if someone out there can get some for you. Or, if you have amazing Photoshop skills, you can always purchase a shot of cacao pods and add it in to your shot. 
