Hi Liz, welcome 🙂
I have had many puppies and dogs and each one is different and needs to be treated as an individual. What works for one won't necessarily work for another.
Introducing the new pup means that your resident dog is scent marking. As the new pup's pong is taking over your older dog is marking his territory.
It seems likely that the garden will also be marked and the pup may feel uneasy about going there.
I am presuming that first you have been to the vet for jabs and worming etc and to check that there is nothing physically wrong? Simple things like testing the pups hearing and eyesight are usually taken for granted but should still be tested.Some dogs learn easily and very fast, others can take a much longer time. Patience is a virtue, not easy though when you have poop everywhere. Imagine what it was like with me with two great German Shepherd pups!
Try and find a puppy training class as that can give you support and an easy way to have access to friendly advice.Jabba mentions Alpha dog, well the owner should always be boss and alpha but I don't think your status is at fault here, just puppy nerves and jitters.
11 weeks is old for a new pup, do you know what happened? Did he get re-homed or something as that may hold valuable clues.Good Luck and lots of anit-bac 🙂
I totally agree with cascara, puppies and dogs each have different traits and charicteristics. Some are independent and aloof, even if they raise by the same person. Others bond closely to one person and are indifferent to everyone.:)
I soon learnt that the word 'No' was my best friend with our new dog, along with the use of a harmless 'Pet Corrector' Spray.