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A Strong Field in This Year’s Sawaya Garden Trials

Grow only a few new varieties each year to evaluate their success in production and at retail.

October 22, 2015  By Melhem Sawaya

Drone-eye view of the 2015 trials

The weather early on this year was great for the Sawaya Garden Trials (just east of Simcoe, Ont.), and this was reflected in the quality of most varieties. We had cool nights (but not too cold!) and warm days (but not too warm!) providing excellent weather conditions for the plants to establish.

So for me, any non-performing variety this season should never be on any retail shelf, grown in a greenhouse, distributed by a broker, or even produced by the breeder.

To benefit from trials, it’s important to apply what we learn next season. It is time to put the horticulture industry on a progressive track that makes consumer success the top priority. Carrying products that look good on the retail shelf but that we suspect won’t perform for the consumer is a total disgrace and lacks integrity.


In our 2014 trials, the downy mildew on Walleriana impatiens did not show up until mid-August, so some growers jumped to the conclusion we can start growing them again. Yes, all that was grown got sold – keeping in mind that only a small fraction was grown – but by July 1 this season, our impatiens walleriana was wiped out by downy mildew. This is short-sightedness because that consumer will shop somewhere else, or even worse, will give up on gardening.

Most of the time at trial gardens we look for varieties that are good performers, which is great. However, what is more effective is to look for the non-performers and eliminate them from our program and send the message to the supplier.

This summer did feature many rainy days, with temperatures below average. It is amazing how fast the recovery is for some plants, and how there is virtually no setback for them at all, while others look like they went through the “heavy duty” cycle in the washing machine. These weaker varieties take five to seven days to recover, mainly from shattered flowers, and face the risk of botrytis if they are not deadheaded. Geranium is the first genus that comes to mind, along with many varieties of petunia, though there are varieties that were not affected by the rain at all.

Many of the varieties that are not supposed to take the heat performed very well, including osteospermum and lobelia, and the flowers lasted a very long time. My conclusion, which is based on observation only, is that flower longevity is related to the average temperature. The higher the temperature, the shorter the flowering. But if plants are outside in full sun and watered well, the flower power and strength is much better even under high temperatures.

Having said that, it is still true that the higher the temperature, the shorter the flower life cycle, especially when light levels are low or the crop is overly shaded. That is why most of the plants, if not all, flower better and the flower life cycle is much longer outdoors in full sunlight than in the shade.

The main purpose of the Sawaya Garden Trials is to see the varieties that perform best in our climate (southwestern Ontario). Throughout the past 15 years, we have seen some genus perform well and others not quite as well. For example, calibrachoa production has increased by over a thousand-fold, not only in Ontario, but throughout Canada. This amazing increase is due to its excellent garden performance, and the excellent show it puts on from early spring to late fall as long as we fertilize it with every watering.

The next genus that is increasing faster than the supply is the Rieger begonia, along with many other begonias.

All trial plants are donated to the nearby Norfolk General Hospital as a fundraiser. Volunteers sell the plants directly at the trial gardens. The buyers are amazed by the quality of the plants, and are happy to pay $20 a pot for annuals…even in late August!

So why are many gardeners not getting the full potential beauty out of their plants, especially late in the season?

The answer is simple; we are not communicating the information effectively to the ultimate consumer. Unless we are planning to shrink our sales by 2.5 per cent every year, we better get together with our buyers (stores and garden centres) and representatives of the greenhouse industry and educate the consumer. This is in addition to doing our homework in selecting the best garden varieties.

Here are some of the same steps I mentioned last year to increase our sales. Normally it takes five years to adopt a change, so I am mentioning it again!

  1. Only grow the varieties that are garden-performance proven.
  2. Sell the plants in larger containers than you are used to using. For example, plant the flats material in much larger cells or 4” pots, and the 4” pot material in 6” pots. Here’s a good rule-of-thumb: if you have to apply growth regulators more than once to make the plant fit into the container, then it is more than likely the container is too small. Examples would include dahlia, Blue salvia, Profusion zinnias, African marigolds, and gazania, to mention a few.
  3. Plant in a good potting media with no weird additives. Delaying plant watering by 12 hours or a day provides a false expectation to the consumer.
  4. Top dressing the containers with slow-release fertilizer could be a setback for varieties that cannot take a heavy dose of fertilizer all at once and that will happen in high temperatures. This is because all the slow-release fertilizers are released based on temperature and especially if the plants are not getting enough water on time.
  5. Provide liquid fertilizer free, as a bonus, when they buy your plants. Mix it in a 200 L barrel, a thousand times concentrated, so the consumer can dilute it to end up with a solution of approximately 150 ppm.
  6. If we do nothing else, we must sell simplified drip kits so the homeowner can water their plants effectively and regularly. I guarantee you that plant sales will increase three to four per cent every year rather than decrease by two to three per cent.

I have first-hand experience with people who visit our trials and ask about our drip system. I tell them where to buy it and the simple steps needed to put it together. Those who install the drip system make it a point to come back and thank me for the hint. They also tell me they are going to buy many more plants because they know the plants are going to do well without any more work.

Get involved in advertising plants and their benefits.

In this industry, there is no sitting on the fence. If we are not part of the solution, we are part of the problem.

If anyone has any suggestions of how to gain consumer confidence or help sales, please share them with me so I can include them with these suggestions. No, you will not lose sales by sharing your ideas; on the contrary, your sales will increase because as an industry we are trying to ensure consumers are successful with our plants.

Here are some highlights from our trials this summer.

It is not very practical to try to share with you the performance of all 2,400 cultivars, so this year I decided to pick a few cultivars that were excellent performers that I call Gardeners Repeaters (GR). These varieties are not in any order.

Remember, if you have never grown any of these varieties before, just grow a low percentage of your production to evaluate their success in production and their consumer appeal. You can then decide to increase production or drop them. If you decide to increase production of a new variety after trialling it for a season, make sure you take a good look at which variety you can drop.

With the popularity of calibrachoa, you can now choose the colour size and habit. Breeders are doing a great job of classifying the series according to habit, which helps in deciding container size for each variety.

‘Calipetite Mid Blue’ (1) is a compact calibrachoa variety that can be grown in a 4” pot using hardly any growth regulator. It is also ideal in mixes where varieties with the same vigour are planted together.

‘Cabaret Blue Deep’ (2) is a medium growth habit calibrachoa that will work well in 10” hanging baskets and in combination with other colours as the series is very homogeneous.

And if you need a more vigorous variety, ‘Dark Blue Improved’ is a good choice that will work in large hanging baskets to provide a sizable product that will reflect the size of the basket.

All three varieties performed especially well in our trials. They were all planted in 14″ pots and thrived in the cool, the heat and the rain.

‘Garvinea Sweet Sixteen – Salmon Pink’ (3) is one of many colours in this series. The main advantage of Garvinea gerbera is that it is very mildew resistant. As matter of fact, I cannot see any powdery mildew even though I am writing this article in mid-
September and the plants are still showing new flowers. Garvineas are successful in pots or in beds, as we trialled them in both!

‘Moonlight Dark Red’ (4) is a robust geranium variety of a great series for garden performance in hanging baskets, combinations or landscapes. The days of compact early flowering are gone because some of those varieties are cute at sales time but have poor garden performance. Look for vigorous, sturdy varieties with flower colours that you like and for the garden performance – the bigger the better as long you fertilize and water.

‘Royal Salmon’ (5) and many other Ivy geraniums performed much better than other years. As matter of fact, this is the first year I have seen such good ivy geraniums, other than the interspecific or balcony types. I have to wait until next year’s trials before I can make a clear decision on ivy geraniums, but the Royal series certainly performed very well this year.

‘Crescendo Yellow’ (6) is not a new osteospermum, but it is a vigorous habit variety that will flower all summer long. The Crescendo series is under-used because of the misinformation on its flowering in cool temperatures. For the past 12 years, we have had the Crescendo series in our trials and they always put on a great show the whole summer. Crescendos are great alone, but they will shine with other vigorous cultivars.

‘Stratosphere Pink Picotee’ (7) is quite impressive. In every trial for the last 11 years, I’ve found gaura to have the most attractive varieties and they are liked by almost everyone. However, it does not sell well in garden centres because it does not put on a great show unless it is displayed in large numbers. It will show very well at retail if it is planted in large containers with multiple plants. It will also do great in mixed containers as a centre plant.

Bracteantha ‘Sundaze Golden Beauty’ (8) always performs well in the garden without deadheading. Rain doesn’t dampen its spirit! It performs well the whole season, which makes it ideal in combinations and especially those for the fall. And if yellow is not the colour you want, there are many others to choose from.

‘Sunsatia Lemon’ (9) will be popular. At last we have virus-free nemesias that flower the whole time. Sunsatia has a great flower power with blooms that last a long time. It is excellent in landscapes, large containers and combinations.

‘Endurascape Blue’ (10) is not like other verbenas because it holds its flowers longer than most others, which makes it a breakthrough in verbena breeding. Endurascape is a viable plant in combinations without having the agony of deadheading it even in the greenhouse like many of the other verbenas.

‘Dragon’s Breath Red’ (11) represents new breeding in celosia. This is a very vigorous variety that is red in colour with mounded tassels. What I especially like about it is that it grows in hot or cold weather. After the first three weeks of planting in ground beds, it will need minimal watering because its roots go deep. It does not need any deadheading. Dragon’s Breath is a facultative plant, meaning it will flower without short days, though short days will enhance flowering. Our plugs were never in short days but they were outside in full sun. It is exactly like African marigold regarding flowering.

‘Deep Apricot’ (12) is one of the colours in the Profusion zinnia series that puts on an excellent show every summer. The low input cost and short growing time gives gardeners total enjoyment the whole summer. It can be grown in pots, and the larger the pots, the better the show. Profusion is great in landscapes.

‘Bounce Violet’ (13) and ‘Sunpatiens Spreading Tropical Orange’ (14) are two different impatiens series that are resistant to downy mildew even if they are planted in a bed that was
infected with downy mildew the year before. I trialled both series the past few years and they have excellent garden performance the whole summer. Bounce has lots of flowers but they do not last as long as the Sunpatiens. However, they regenerate new flowers much faster than Sunpatiens. Both series are winners, so stop messing around with the wallerianas and grow a much superior series.

‘Joy Yellow’ (15) is a non-stop begonia that has a mounding habit that can keep growing without breaking. It has dense foliage and a tight growth habit. Many colours will be available. We grew Joy in full sun with no negative side effects.

‘Beauvilia White’ (16) is a trailing begonia that looks great in hanging baskets. It has lots of flowers and branches very well, which is characteristic of the Beauvilia series. Make sure to try some because it is getting a positive response from consumers and is fairly easy to grow. Remember, it is a tuberous begonia so long days are needed until at least March 21.

The begonia hybrid ‘Unstoppable Upright White – Salmon’ (17) is impressive. The whole series has an upright habit with sturdy stems especially when grown in full sun. It is a must to grow all begonias in full sun if you want them to be able to handle the outdoor sun. It is excellent in landscapes or large containers.

‘SuperCal Artist Rose’ (18) is one of the many colours in the Petchoa series. It is an excellent performer in the garden that recovers from heavy rain in one hour or less and the flowers last a long time. No deadheading is needed because there is more than a flush of flowers formed before the second or third generations are spent. Petchoa is great in large baskets and in combination with other Petchoa colours, or with other cultivars or genera.

Kombos ‘Pink Lemonade Mix’ (19) is one of the best combinations I have seen in the greenhouse. Throughout the whole season outdoors, all the varieties gel together to give a synergetic effect. Many of the other mixes look great in the greenhouse but turn ugly within three weeks of being outdoors. Trialling the combination before marketing it will bring the customers back for more.

Tidal Wave (20) is an old series that has garden performance that exceeds most other petunias. Tidal Wave is vigorous and never stops flowering. There is no setback by rain and no botrytis issues. Plant in early April to get a large container by or before the long weekend in May. Tidal Wave is great in landscapes, too.

‘Supertunia Vista Mix’ (21) has been a star in our trials for the last five years. As a matter of fact, it is a cousin to the Tidal Waves (if not a half-sister). It is an excellent performer that requires no deadheading. There is no downtime because of rain and it puts on a show that is second to none.

The trial pictures will be posted on my website at

Melhem Sawaya of Focus Greenhouse Management is a consultant and research coordinator to the horticultural industry –

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