Trials & Tribulations of Growing Perennials

Susan Martin

So you’re thinking about getting into the business of growing finished perennials. Maybe you’re an experienced annual or shrub grower thinking about expanding your product lines or maybe you’re completely new to the business. No matter where you begin, there are a few key understandings you’ll need to start off right.
If you’re already a grower, you understand the fundamentals of production—growing media, fertility, irrigation management and pest and disease management. Beyond these basics, growing perennials requires further understanding about vernalization, scheduling, overwintering and more.

Five common fears
The amount of information growers need to know before getting started in growing perennials can be overwhelming. It’s completely normal to have questions and you can avoid common mistakes by doing your homework before you begin.

Fear #1: I don’t understand vernalization. Will my plants flower?
The term vernalization simply refers to the chilling requirement many perennials need to produce flowers. Most perennials require vernalization to bloom, but a few key crops—like perennial hibiscus and coreopsis—do not. Other crops like sedum and salvia greatly benefit from vernalization,
but will bloom without it.

Northern growers have the natural advantage of winter for vernalizing their plants, but all growers can purchase plugs and bare root plants that have already been vernalized from their suppliers in late winter or early spring. Consult your suppliers on the cold requirements of all perennial crops you wish to produce before you buy in your starter materials.

Fear #2: I don’t know where to start! What starting materials do I need?
If you’re brand new to perennials or are unfamiliar with bare root material, it may be best to start with large plugs, which are easy to plant and quick to finish. Once you build some confidence, try starting a few easy crops like hibiscus and hemerocallis from bare root (Figure 1). Many perennials started from bare root finish faster and are larger finished plants than those grown from plugs. You may also consider starting with newer genetics that have proven to be more vigorous and trouble-free in production.

Figure 1. If you’re brand new to growing perennials, you may want to start with more familiar plug material. Once you have some experience under your belt, try growing a few crops from bare root. They often finish faster and become larger finished plants than those grown from plugs.

Fear #3: I don’t know how to force perennials into bloom for different seasons.
Forcing perennials is a bit of an art and requires some trial and error. As a general rule of thumb, pick a date that you want your finished perennials to be ready to sell, then work backwards from that date to determine your planting date. Perennials started from large plugs or bare root typically take six to eight weeks to finish in trade gallons, while small plugs can take up to 12 weeks. Once they’re fully rooted, more time will be needed for the plants to come into bud and bloom. Look to your suppliers to provide specific planting recipes and to books like “Perennial Solutions” by Paul Pilon or the Ball Redbook edited by Jim Nau for valuable detailed growing advice.

Fear #4: Won’t my losses be greater if I lose some perennials than if I’d just grown annuals instead?
While losing money is always a concern, with greater risk comes greater reward. The inputs and growing costs for perennials may be greater than for annuals, but they also garner higher margins.

As with all plants, there’s a learning curve when growing perennials. If you’re new to perennials, start with some failsafe crops and work your way up into more specialty items. Tip: Perennials that are easy to grow in the garden are NOT necessarily easy to produce in a greenhouse. A classic example is echinacea (Figure 2)—an easy native to grow outdoors, but challenging in
production.

Figure 2. (left) Perennials run the gamut from easy to challenging depending on the cultivar, and just because something is easy to grow in the garden, does not mean it’s easy to grow in production. A prime example: echinacea.

Fear #5: How do I keep my perennial crops alive over winter?
Not all growers have the facilities or capabilities to overwinter perennials. If this is true for you, start your perennials in early spring from vernalized bare root material or large plugs. If you decide to plant some of your perennials in late summer or fall prior to sale and overwinter them, talk to other local growers about what overwintering techniques have worked successfully in your climate. Factors such as snow cover and temperature fluctuations over the winter months can greatly impact the success of overwintering perennials.

Five common pitfalls to avoid
Growers who are experienced in annual or shrub production tend to commonly make a few simple mistakes when growing perennials. Understanding these pitfalls ahead of time can save you money, time and frustration.

Pitfall #1: Using the same growing media for annual and perennial crops
Solution: While annuals typically require a growing media that has good moisture retention, perennials are very prone to rot if grown that way. Instead, choose a bark mix with peat and perlite that will provide good drainage for these longer-term crops.

Pitfall #2: Planting out of season
Solution: Scheduling is a critical skill to learn when growing perennials. If you have overwintering capabilities, it will save time and labor if you plant some of your crops in late summer or early fall prior to sale. Fall planting is especially critical for early spring-blooming crops, like primrose and aquilegia, which tend to bolt into flower before setting roots if planted in spring.

Figure 3. (left) Hostas planted the summer prior to sale (photo right) develop more eyes, a better root system, more mature traits—including proper variegation—and have a much higher perceived value compared to those planted and sold the same spring (photo left).

When you plant perennials the year prior, the finished plants will have larger crowns and root systems and will be more floriferous than if they were planted in spring (Figure 3). Their perceived value will be exponentially increased and they can garner higher prices. As your greenhouses empty out in spring, backfill them with newly potted perennials to finish for summer and fall sales.

Pitfall #3: Growing perennials too warm and fast
Solution: Annual growers who are new to perennials often make the common mistake of turning up the heat too high on perennials to force them in spring. While there are some perennials that like to be grown warm, as a general rule of thumb, slow and cool wins the race with perennials. When waking up dormant perennials in spring, providing a cool growing environment will result in sturdier, fuller, more compact plants.

Pitfall #4: Not being equipped to ship finished perennials
Solution: Perennials are typically sold in quart and gallon-sized containers and their height varies throughout the growing season. You may need more racks with adjustable shelves to accommodate various crops. They’ll be heavy and costly to ship, so you’ll need to carefully calculate the freight per plant when developing your pricing model.

Pitfall #5: The challenges of marketing and selling a new product category
Solution: If you’ve built a reputation for being a reliable annual or shrub supplier, you have a built-in base of potential customers for your new perennial line. However, your current customers may not produce enough demand to meet your new sales goals.

Before you begin, ask your customers about their interests in perennials, which crops they would be most likely to purchase from you and what time of year they would need delivery. Set your sales manager on a mission to find potential new customers for your new perennial line and develop a solid marketing plan to reach those people. Then train key members of your staff to troubleshoot your customers’ growing issues, which will surely arise.

Growing finished perennials can be a very rewarding and profitable business. Start with good material from a reputable supplier, learn from your mistakes and be willing to make changes in your production model to be more successful. Look for more of the nitty-gritty technical details of growing finished perennials in upcoming issues of GrowerTalks. GT

Susan Martin specializes in horticultural marketing, content generation and management, working with green industry clients in trade and consumer sectors. She can be reached at gardenersuesnews@gmail.com.