How to Choose and Purchase Perennials

by Judy Kautz, OSU Extension Master Gardener

Spring is here and your local garden center has new perennial plants for you!  Choosing plants from rows and rows of the same type of perennial can be daunting, especially when you want to pick the very best one to take home.  Which plant do you pick when some have buds, some are blooming, and others only have foliage?  Here are some selection tips to make your shopping trip easier.

First, do you choose plants in full bloom?  Not really, since they have already bloomed and the blooms may not last much longer.  Pick instead the plant that has buds or the beginnings of flower spikes as your best option.  A plant like this is best, because you can see just enough of the flower to be sure you are getting the cultivar and the bloom color you want.  Remember that plants do get rearranged by customers, so the sign in front of plants may not necessarily reflect what is there!  Tags in pots also get moved around, so seeing the beginnings of the bloom will tell you what you are buying.
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Next, size definitely does matter.  Most often, the largest plant is your best option unless it is leggy.  Also, look at the root system to ensure the plant isn’t root bound; a root bound plant (one with a dense mass of roots) can recover, but it will take time.  A medium sized plant could root faster with healthier looking foliage after being transplanted, but it might not grow much more this year.  Never buy the smallest one if it is the same price as the others, as you will overpay.

Here's an example of a plant that has been root bound in a pot. Avoid these when purchasing perennials unless you are getting a deep discount.

There are some perennials that you should always buy bigger because they are slow-growing; plants like false indigo, Russian sage and peonies fall into this category.  Buying the largest plant you can find of these varieties means you will get a bigger impact sooner.  With peonies in particular, look into the crown for the plant with most eyes or stems; since peonies are so slow to take off, the more stems, the better.  Finally, if you are simply looking for a great deal, choose a plant that is spilling out of its pot, because it can easily be divided into several plants for the price of one.

When purchasing perennials like these peonies, buy larger plants with more stems.

If you see plants that are deeply discounted because of damage, or you see a plant you think you might be able to revive, those can be difficult to pass up.  However, carefully examine the plant first before you decide to spend your money.  It will not hurt a plant to look at its roots; simply straddle stems with your fingers and gently tip the top. 
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Here are some things to look for if you are considering buying a damaged or deeply discounted plant.  Avoid a plant that has been newly transplanted, with roots that don’t fill the pot.  Although it is okay to buy if you get a really good discount, remember that it will be a long time before it takes off in your garden.  Second, look for pest damage – lacelike holes in discolored foliage – most likely caused by Japanese beetles.  These insects can mark plants for others to find later, so skip insect-damaged plants.  If you see shriveled brown or pale leaves, the plant has not gotten enough water or protection from strong sun.  If foliage looks really stressed, this plant will rarely bounce back, so leave this one on the shelf.  Finally, avoid plants with dead crowns or roots that are easy to pick off; these are signs of overwatering.  Since rotted roots never recover, do not buy overwatered plants.

Plants for sale which demonstrate insect damage like this one should not be purchased, even at a discount.

​If you follow the tips when you choose your perennials, you should bring home plants that will flourish in your garden.  And to see many examples of all kinds of plants, visit the Master Gardener Demonstration Gardens at the Cleveland County Fairgrounds, southwest corner adjacent to the gravel parking lot.