Quarterbacks don’t grow on trees.

That’s what John Elway said after Thursday’s joint practice with the San Francisco 49ers when asked what he sees in his young quarterbacks, Trevor Siemian and Paxton Lynch.

What Elway was saying, really, was that his young quarterbacks need time to germinate.

Don’t think of Siemian as Lynch and Siemian as ripe apples to be plucked and dropped in as the main ingredient of a Super Bowl pie. They’re still seedlings, growing and yet to blossom in the NFL. That growth happens from the ground up.

Here’s the full quote from Elway:

“I’ve got confidence in the fact that they’re both young and they’re going to continue with practice and getting better. That’s why I had confidence in it. I think that looking at the guys that we have, and them wanting to go and compete in practice, they don’t grow on trees. There are not quarterbacks grown on trees out there, so there wasn’t another answer. So with that being said, I like the guys that we have because I know talent-wise they can do it, it’s just a matter of they need the time and experience and with that they’ll continue to get better.”

With a combined 16 NFL starts under their belts, what Siemian and Lynch need – more than anything else – is time. They also need improved play around them.

49ers head coach Kyle Shanahan told Eric Goodman and Les Shapiro just as much when he spoke with them on Mile High Sports AM 1340 | FM 104.7 after his team’s joint practice with the Broncos on Thursday.

“He’s tough enough to stay in the pocket,” Shanahan said of Siemian. “It’s about guys getting better as they go and guys playing around him better.”

Last year Siemian suffered an injured left shoulder in a Week 4 matchup with Tampa Bay, when he was sacked three times in less than two full quarters of play. He was never quite the same through the remainder of the season. Siemian missed two starts (Week 5 against Atlanta and Week 13 against Jacksonville) because of injury, forcing Lynch, then a rookie and still learning the NFL game, into action.

In that Week 5 home loss to the Falcons, Shanahan, then Atlanta’s offensive coordinator, saw firsthand the strengths and weaknesses of Lynch’s game.

“He’s got a strong enough arm to make any throw,” Shanahan said.

He also saw enough to know what Lynch needs to take the next step.

“It’s really about reps, developing as a quarterback, how you do play in that pocket and then when the pocket’s not good, when stuff breaks down, can you not hesitate and turn into the athlete that you’ve been most of your life and make those plays,” he said.

Time and better play around them. That’s what Siemian and Lynch need to grow into successful quarterbacks. Elway knows it.

“Obviously that position is very, very important,” Elway continued on Thursday. “We’ve got better around them to give them better opportunities to be successful. There are still going to be growing pains. Whoever becomes the starter during this year, there’s still going to be growing pains because they’re both so young.”

Even Peyton Manning wasn’t the perfectly ripe apple waiting to be picked when Elway signed him in free agency in 2012. Manning had dropped from the branches and was scooped up from the ground when others were fearful he was ready for the worms.

Siemian and Lynch are in their third and second years in the league. They need time to grow, time to develop. Elway clearly understands that, and appears to have the patience to let it happen.

“Like we said, he’s making progress,” Elway said when asked about Lynch, being sure not to exclude Siemian.

“They’re all making progress. But I think what you saw in Paxton today is he played with a little more confidence than he has in the past. I think anytime he does that he’s a lot more successful. That comes with youth too. You have your ups and downs as youths and the consistency is not there where you want it to be. That’s why you continue to practice, continue to work and continue to get better.”

Or, in other words, to continue to grow.