It would be easy to think that the cannabis industry is in a state of malaise if you only looked at Canadian marijuana stocks. All of the biggest Canadian pot stocks are down year to date.

But it's a different story in Canada's southern neighbor. Quite a few cannabis companies that focus on the U.S. market have delivered fantastic performances in 2020. Some of them appear to be poised to keep the good times rolling. Here are three top marijuana stocks to buy in September that are solidly in that group. 

Cannabis leaf on a $100 bill covering part of Ben Franklin's face

Image source: Getty Images.

1. Green Thumb Industries

Green Thumb Industries' (OTC:GTBI.F) shares are up more than 40% year to date. And that doesn't really reflect just how well the stock has performed in recent months. GTI's shares have soared more than 240% since mid-March, when the stock bottomed out following the overall market meltdown.

The U.S. cannabis operator delivered outstanding results in the second quarter. GTI's sales jumped 16.6% quarter over quarter and 167.5% year over year to $119.6 million. In the first half of this year, the company's revenue topped its revenue total for all of 2019.

I think that GTI's remarkable growth will continue. The company now has 48 retail cannabis stores in 10 states. It owns licenses for another 48 retail dispensaries. GTI has also shown that it can grow even amid a pandemic and a challenging economy. As CEO Ben Kovler put it, "Demand is strong as cannabis continues to behave like a consumer staple."

The only notable flaw for GTI is that it's not profitable yet. However, the company's revenue is growing at a much faster rate than its expenses. It shouldn't take too long for GTI to achieve profitability. In the meantime, the company has plenty of cash to tap as needed.

2. GrowGeneration

GrowGeneration (NASDAQ:GRWG) ranked as the top-performing marijuana stock in the first half of 2020. It's continued the sizzling momentum recently as well. Shares of the specialty hydroponic and organic gardening retailer are up more than 260% year to date.

In the second quarter, GrowGeneration's revenue jumped 123% year over year to $43.5 million, an all-time high. The company's net income increased to $2.6 million from $1.1 million in the prior-year period. 

Some of GrowGeneration's strong performance was due to the COVID-19 pandemic, with more consumers taking up home gardening. However, a lot of the company's growth stemmed from a general boom in the U.S. cannabis market. 

GrowGeneration looks expensive, with shares trading at 125 times expected earnings. My view, though, is that the stock will continue to climb as the company moves toward its goal of nearly doubling the number of retail stores it operates by the end of next year.

3. Innovative Industrial Properties

Innovative Industrial Properties (NYSE:IIPR) stands out as another U.S. cannabis stock that's delivered a strong performance so far this year. Its shares have soared more than 60% in 2020. Investors have also benefited from IIP's increasing dividend, which currently yields close to 3.4%.

The company generated revenue of $24.3 million in Q2, up 183% year over year. IIP's second-quarter net income of nearly $13 million more than quadrupled its earnings in the prior-year period. 

What's the secret to IIP's success? Its "rinse-and-repeat" business model. IIP buys properties from medical cannabis operators then leases the properties back to the operators. This provides a solid revenue stream for IIP that it reinvests in purchasing even more properties. 

Perhaps the biggest threat to IIP is marijuana legalization at the federal level in the U.S. If medical cannabis becomes legal nationwide, more companies could enter the cannabis real estate capital market. While this scenario could happen, I still think that IIP will be able to keep rinsing and repeating its way to sustained long-term growth.