For buy-and-hold investors, the trading action since March 2009 has vindicated the strategy of buying high-quality companies and staying put for the long term. Yet quite a few high-quality names have also moved lower recently, giving long-term investors an opportunity to potentially scoop up great stocks at bargain prices.

What makes some of this year's bargains so enticing is that a few of these high-quality companies are growth stocks. Though the term "growth stock" can be completely arbitrary, I prefer to define a growth stock as a company that has the capacity to grow by 10% or more per year. Growth stocks are operating in an especially friendly environment at the moment, with lending rates still well below their historic average, even after three rate increases. This is giving growth companies the opportunity to reinvest in their business, hire, and acquire for relatively minimal borrowing costs.

Progressively higher stacks of coins and a sprout coming out of the ground, with a hand placing more coins on the largest stack.

Image source: Getty Images.

After perusing a list of growth stocks that are down more than 10% over the trailing 12 months, three stood out as being attractively priced for long-term investors this spring.

Alexion Pharmaceuticals

If you're looking for a rapidly growing bargain in the biotech space that's currently going through a bit of a rough patch, then rare-disease drugmaker Alexion Pharmaceuticals (NASDAQ:ALXN) could be the bargain stock for you this spring.

Alexion has faced a small army of bad news recently. In late December, the company announced that Soliris failed to meet its primary endpoint in the phase 2/3 delayed graft function trial known as PROTECT. It also delayed the filing of its third-quarter results and had both its CEO and CFO abruptly resign with an accounting probe ongoing surrounding sales of Soliris. There's obvious concern that Soliris' label expansion opportunities may be more limited than expected, and that Alexion could run the risk of being taken off course by a new management team. And, of course, there's concern that President Trump's push for drug-price reform could derail Soliris.

But I see opportunity among the perceived peril. For instance, Soliris, which is one the most expensive drugs in the world, is unlikely to be hurt if President Trump is able to pass drug-price reform legislation, which I don't see happening with Republicans in control of Congress (Republicans favor free-market pricing). Soliris focuses on ultra-rare ailments, and it would be incredibly difficult for lawmakers to take the incentive of recouping development costs away from drugmakers in the rare disease segment.

A doctor high-fiving a child on her mother's lap.

Image source: Getty Images.

Alexion also has a growing early stage pipeline, as well as a new therapy that could yield blockbuster results in Kanuma. A treatment for lysosomal acid-lipase deficiency, Kanuma was the primary dangling carrot that coerced Alexion to buy Synageva for more than $8 billion in 2015. 

With sales growth likely to come in between 10% and 20% annually over the next four years, and Alexion's full-year EPS expected to more than double to almost $11 by 2020, this is a growth stock that could bloom for investors soon enough.

Under Armour

Another company that's been absolutely railed by Wall Street and investors over the trailing year is Under Armour (NYSE:UAA) (NYSE:UA).

The active-apparel retailer has shown rare signs of weakness of late, with its fourth-quarter report highlighting just 12% sales growth, of which U.S. sales grew by only 6%. The company's quarterly report hinted that Sports Authority's bankruptcy didn't generate additional sales as expected, causing its inventory levels to rise and coercing margin-cutting discounting to move product. Since investors had been buying Under Armour as a growth story, its slower fourth-quarter growth has caused Wall Street to reassess the company.

However, I see opportunity amid what could be a multiple quarter hiccup for Under Armour. Probably the biggest area of intrigue is what it can do once it really begins to penetrate overseas markets. International sales only represented 15% of total revenue for Under Armour in 2016, yet it reported 69% currency-neutral international sales growth for the year. International expansion is certainly on Under Armour's radar, but it won't happen overnight.

A still shot of Julius Jones carrying a football in Under Armour gear.

Image source: Under Armour

Direct-to-consumer sales growth is also a bright spot for the company. E-commerce sales contributed to 31% of all revenue in 2016, and sales grew 27% overall last year. E-commerce allows Under Armour a more efficient way to operate with lower overhead, while also giving the consumer more convenience and choice.

Investors also shouldn't discount Under Armour's brand ambassadors, which are among the top names in their respective sports. Athletes such as Steph Curry in the NBA, Cam Newton and Tom Brady in the NFL, and Clayton Kershaw in MLB, draw in customers from young to old.

If Under Armour sticks to expanding internationally, focusing on e-commerce, and innovates with new product, it'll likely continue growing by a double-digit percentage and bring its P/E ratio way down by 2020. It may not look like it now, but Under Armour could be a bargain worth grabbing off the clearance rack this spring.

Sprouts Farmers Market

Last but not least, organic and natural food grocer Sprouts Farmers Market (NASDAQ:SFM) could be worth a look this spring, given that its share price has fallen 19% over the trailing 12 months.

Sprouts has been experiencing growing pains over the past year. Competition in organic and natural foods has been heating up from both grocers focused on organic and natural foods, as well as the majors, which are placing more emphasis on these higher price point products in their stores. The result has been weaker year-over-year same-store sales growth for Sprouts. Food inflation has also been weak, which is suppressing margins.

The inside layout of a Sprouts Farmers Market grocery store.

Image source: Getty Images.

Fortunately, this weakness could be temporary, with a number of positive catalysts on the horizon. Front and center for Sprouts Farmers Market is the fact that Americans spent $43 billion on organic food in 2015, marking the fourth consecutive year that organic food growth touched a double-digit percentage. The ongoing push toward a healthier and more nutritious lifestyle in America is likely to fuel superior growth for organic foods. Plus, consumers expect to pay more to receive a natural or organic product, so Sprouts isn't having to deal with much in the way of discounting to move its inventory.

The possibility for consolidation is also working in Sprouts' favor. According to Bloomberg, major grocer Albertsons held preliminary merger talks with Sprouts recently, with the idea being to take Sprouts private. A buyout would allow Albertsons to realize the instant benefits of Sprouts' organically focused growth, and it would presumably augment its traditional grocery business nicely.

Expansion offers another avenue for success, as Sprout is only operating in a little over one dozen states at the moment. There are opportunities for it to expand into a number of new markets in the years to come, which would only add to its already impressive growth.

With double-digit annual sales growth expected for the foreseeable future, Sprouts Farmers Market could be worth putting in your basket. 

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.