I received a question from someone who is growing strawberries for the first time. He has heard that strawberries live for three years and wanted to know if it was because of weeds, nutrients, or what. Here’s my reply:
Strawberry plants can live many years. All of the things you mention can be discouraging. In my experience weeds tend to take over before other factors become important. With good mulching and planning weeds can become less of a factor.
The three year thing is about the need to renovate the plants after a period of time. Organic matter breaks down and is depleted over a couple of years.
The soil structure is no longer able to hold moisture. The mass of roots of older plants quickly takes of water and the soil can’t hold enough water to provide the moist soil that strawberries need. Nutrients get depleted and are hard or impossible to incorporate. Most nutrient application is done as top dressing which is a very inefficient way of getting nutrients to the roots.
With alpines, I have found an additional reason to renovate after a period of time. Unpicked fruit results in volunteers. Self pollinated fruit (pollen from the same plant) and cross pollination of different varieties can result in what appears to be new types of plants coming up and producing fruit.
This is particularly apparent in plantings of white/yellow fruiting varieties. White/yellow fruit is recessive. A lot of crosses will result in the new generation producing red fruit. Non runnering types (clumping alpines for example) can produce volunteers that produce runners. As you can see this can get messy over time without some supervision and prethought.
January 15, 2014 By Leave a Comment
I get frequent questions about seed saving and about whether different strawberry varieties will cross. The short answer on crossing is that varieties in the same species will cross. It is not common to have crosses between different species. Hybrid garden strawberries, Fragaria x ananassa, for example will not cross with alpine strawberries, F. vesca. Hybrids have 8 sets of chromosomes (octoploid) while alpines have 2 sets (diploid).
Before leaving the question of crossing, let’s address the question of whether a gardener needs to isolate different varieties. If you are not saving seed there is no need to separate varieties of a species. Yes, they will cross but it will not affect the flavor or taste but it will affect the genetics.
All of this is important to know if you plant to save seeds. If you are growing one selection of alpine strawberries such as ‘Alexandria’ you don’t have to worry about it crossing with hybrids in your garden so you can save the seeds for the future. One thing to be aware of though, is whether there are other plants in the vicinity that will cross with an alpine. There may well be wild diploid strawberries in the area such as in the wild or those being grown by neighbors. If there are insect pollinators in the area they can cross the plants. The wind can carry pollen from distances that could cross with your single alpine variety.
If you’re getting the idea that isolation by distance may not be enough then you are catching on. Several strawberry experts have told me that plants that could cross with each other should be at least a half mile apart but to be on the safe side it should be a mile. If there are single plants or isolated patches of plants that can cross with your plants, a half mile should be sufficient. If there are large plantings within a half mile then a mile would be better. It’s all about the probability of crossing.
Are there alternatives to isolation by distance? Fortunately, yes! Isolation can be accomplished with barriers. There are many types of barriers. One might be a large planting of trees such as a forest. Mountains can isolate plantings. Even your house can provide a barrier. These barriers need to keep the wind from cross pollinating similar plants and keep bees from carrying pollen to similar plants. As you can imagine some barriers will be effective while others will not eliminate all risk of crossing.
The best form of isolation is a cage or container. We use pollination cages for our seed production. These consist of insect barrier quality netting and placement of the cages so that the wind cannot carry pollen from one cage to another. Where there might be risk of crossing we select different species for adjacent cages. We have frames that can be covered with plastic to isolate similar plants. Thought has to go into the plan for seed saving on this type of scale.
Keep in mind that plants in a cage still need to pollinate. If wind and air movement are reduced or eliminated than wind pollination will not be effective in pollinating your plants. If the plants are covered with a cage before they bloom there may be few or no insects in the cage to pollinate the flowers. We use mason bees to pollinate in our cages. One option is to hand pollinate but one must be careful when entering the cage to not let insects in. It’s a bit tricky but the main point is that there must be a well thought out plan.
November 18, 2013 By Leave a Comment
Within the last couple of days there has been a spike in emails and phone calls about seeds. The most asked question to date is whether our seeds are GMO. The answer, we signed the safe seed pledge which means that we do NOT sell GMO seeds. All of our seeds are open pollinated and are not hybrids.
We do sell some heirloom plants that are hybrids but none are GMO. They are propagated vegetatively which means by rooting their runners, so they are not open pollinated.
A couple of notes about seed availability and price. So far we are holding our prices or offering better prices and more discounts than in the past. We don’t know how long we’ll be able to do this. Some of the seed is now grown here in Delaware but a still significant amount is imported. The U.S. dollar is weaker than it was a year ago but we are pretty well stocked up right now. We likely will have some shortages as the season goes on, especially for seed we produce.
One other factor affecting availability is a significant increase in demand for seed from outside the U.S. Several species and many of the selections we offer are not available at all or to any great extent off shore. This is especially true for Fragaria virginiana and many of our F. vesca selections.
We are still making the transition from plant production to seed production. If demand for seed continues to increase we will likely significantly reduce our plant production and sales. Many of our customers are either garden centers or growers who grow for garden centers. With shipping costs being what they are it’s probably for the best if we ease back on plant production. It will be much more economical for gardeners to buy plants locally than to have us ship them across the country. It comes down to shear economics.
One last point. Most strawberry seed takes about 14 weeks from sowing to first fruit if grown in a range of 65 to 75 degrees F. This knowledge will help you to plan your sowing and also your seed purchases. Seed can be stored in a freezer prior to sowing and actually should be frozen for at least a month before sowing. All strawberry seed that we ship is already preconditioned and ready to sow. If you get the seed early or if you are a distant international customer who has to wait up to a couple of weeks to receive your order, freeze the seed until you are ready to sow to help optimize germination.
October 11, 2013 By Leave a Comment
I just became aware of an interesting site that gives a very nice and accurate description of alpine strawberries. Nice pictures too! check it out at
October 3, 2013 By Leave a Comment
Click this link to access the subject newsletter
September 28, 2013 By Leave a Comment
The growing season is winding down and most of the planting has been done for spring. This includes more plants for “hover island”. A part of this process is doing the research to first figure out what we are trying to achieve and secondly choosing, ordering and planting the plants for this plan.
At lot of time is spent with online searches. One of the things I was struck with is the strategy that is used by seed companies who offer seed mixtures for beneficial gardens. For a time I actually considered offering a seed mixture customized for strawberry production. The strategy seems to be to throw in seeds for all plants known to attract beneficials including bees, predators and parasites. One interesting thing about the mixtures that I looked at was that many included what I would consider weeds. Several times I thought to myself, I wouldn’t want my neighbor planting this mixture. Next thing would be their weed seeds infesting my lawn and garden.
This realization helped me to adjust my planning. Because strawberries are an early season crop I started my search for plants that attract beneficials AND bloom early to it can benefit strawberry production and early season pest control. There are a few shrubs and trees that bloom early but I’m looking for short term annual and perennials.
Before actually making choices from the short list of early spring flowering plants I wanted to make sure that attractiveness to mason bees is considered. It turns out that having plants bloom all spring and summer is not necessary for mason bees. The adults basically live about six weeks. A spring strawberry crop here in zone 7 blooms in mid to late April. So, now we’ve bracketed the time frame. We were looking for plants attractive to mason bees and other beneficials during April into May.
What we came up with are golden alexanders (Zizia aurea), bulbs like anenome and scilla and dandelions. We have been growing dandelions for edible greens so they will serve double duty.
One more thought for today …. orchardists who are using mason bees to pollinate crops like almonds have noted something very interesting. They recommend mowing the dandelions while the almonds are blooming because the bees need to be pollinating the almonds, not foraging on dandelions – weeds. I plan to keep a notebook with me to jot down observations on:
- date of flowering for each plant
- insects on the plant and flowers
- do the bees prefer another plant over the strawberry
June 15, 2013 By Leave a Comment
Strange title? We are venturing into a new area on this blog. This is all about beneficial insects, companion planting, garden insectaries, and many other terms. This post will introduce the subject.
We have been trying to figure out the best way to approach this large and new area. We considered setting up a separate website and even a separate blog. For now, I think the best place to start is here.
The reason for “Hover Island”? One term used when someone creates a habitat for beneficials is to call the area an island. Hover comes from Hoverflies. Our whole intention is to create a habitat that will increase hoverflies in our nursery area. For a long time we have search for information on this very important group of insect species. Hoverflies are also called syrphid flies.
Why syrphid flies? First, the adults are active when temperatures are around 55 degrees. Here in Delaware these temperatures are typical of April when strawberries are blooming. The adults are effective pollinators. We have started using and releasing mason bees in the nursery and are using them in pollination cages. We have found them to be very effective. But, you can never have too many pollinators, especially pollinators that are present and more importantly active very early in the spring.
Syrphids or hoverflies have a second HUGE benefit. The larval stages are voracious predators of aphids and other soft bodied pests. The adults tend to deposit eggs where aphids are present.
It is especially important to keep aphids in check in a strawberry nursery. Aphids can transmit viruses so their control is essential to the long term health of the species and selections we grow and sell.
Our intention is to create what we are calling “Hover Island”. We have already selected and purchased seeds and plants that will be grown for this area. We will get into the specifics soon.
We also want to point out that other beneficials will be welcome in Hover Island and in our nursery. The plants we have selected will attract a wide variety of beneficials including hoverflies. The plants selected are being selected to offer habit to hoverflies all season, not just early spring. We get some fruit production in the fall so having beneficials that will pollinate and protect the fall crop is welcome indeed.
And, last but not least, we are selecting plant species that are attractive to mason bees as well. We had success with using polliantion cages to isolate and pollinate several crops for seed production. The mason bees reproduced. We hope that even with expansion of our pollination cages the mason bees can reproduce enough to sustain themselves so we don’t have to continually buy mason bees. Mason bees is another subject for another post.
Look for more posts in the near future for the category Hover Island and other categories. We will take some pictures to share about this very important undertaking.
June 15, 2013 By Leave a Comment
Fragaria moschata ‘Royal Bauwens’ is a cross of ‘Royal Capron’ and ‘Bauwens’ that we grew from seed. The fruit has a slightly different taste than varieties that we’ve grown up until now. The young plants produced fruit the spring after sowing them. An image of a few berries is here:
When harvested fully ripe the calyx stays behind. The berry on the right separated from the calyx and left behind a little of the top of the fruit.
June 15, 2013 By Leave a Comment
I don’t remember posting an image of Fragaria vesca ‘Deesse des Vallees’. Here’s one taken recently from our seed production area. Such a shame to not be able to taste the fruit. It is very aromatic.
June 15, 2013 By Leave a Comment
We searched for years for this selection and I must say that the wait has been worth it. This is the selection that was used by researchers who sequenced the genome of the wild strawberry – in other words they identified the genetics of the wild strawberry.
One aspect of this selection that we were and are excited about is that it is day neutral and it produces runners. All runnering selections we have up to now are June bearing. We expected red fruit but this selection produces a very tasty white/yellow fruit that are every bit as large as the larges alpines we have grown. The plants produce a lot of runners and at least some of the runners produce flowers while they are still pretty small. We think that this is a winner and plan to have some bare root plants available for fall 2013. Here’s an image that we’ll share.
June 15, 2013 By Leave a Comment
Fragaria x bifera is a hybrid of F. vesca and F. viridis. We have been excited to try this species for quite some time. Very little information is available anywhere about the fruit of this species. Slightly more information is available about the plants. We now know a LOT more about this species after only a few months of growing it. Here’s what we’ve learned:
- The plants are vigorous growers. They aggressivly produce runners as well.
- The plants appear to be day neutral as expected. I say appear to be because time will tell during short days of fall to see how that affects reblooming. As of this date, June 15th, the plants are fruiting and blooming at the same time.
- The fruit is white/yellow. I was very surprises about this. The fruit seems to be larger than F. vesca fruit. One fruit weighed in at 2.3 grams. That’s large for a wild type.
Here’s a couple of pictures.
We are rooting runners and expect to have bare root plants for sale in the fall 2013. Check the shopping cart to price and availability.
June 2, 2013 By Leave a Comment
I’ve been getting a fair number of emails from customers stating that they are glad that I signed the safe seed pledge. Here is one of the responses I sent to a customer today:
“Fortunately, til now those who want to tinker with genetics have left the alpines alone. I fear that won’t last long. The renewed interest in these wild types has caught the attention of the breeders who cannot accept plants for what they are. They think they need to “improve” even what is the best the God ever made. Their idea of improvement is to make them larger and harder so they can be shipped long distances. Haven’t they ever heard of “grow local”? No need to ship those grown locally.”
May 2, 2013 By Leave a Comment
According to most sources there are 103 species of strawberries. In our search for strawberries with taste we have “discovered” about a dozen or so species. Of course the most well known species is the common garden strawberry, Fragaria x ananassa. By the way, the “x” in the name means that it is a hybrid or cross.
We have been primarily interested in F. vesca, the alpine or wood strawberry. Along the way we found F. moschata, the musk strawberry. The scarlet strawberry, F. virginiana was our next “discovery”. Because F. viridis is a diploid we have been interested in F. viridis for breeding purposes.
Recently, we were able to obtain F. x vescana (a decoploid) and F. x bifera. F. vescana is a forced hybrid between a F. x ananassa and F. vesca. F. x bifera is obtained from the cross of diploid species F. vesca and F. viridis. This hybrid occurs naturally in Europe where both species’ distribution overlaps.
We have other species in our collection that we will discuss later. In the very near future we hope to make available plants of F. x vescana and F. x bifera. We recently added pics of F. bifera to our Facebook page.
May 2, 2013 By Leave a Comment
Other posts have touched on the subject of renovation. I have found through the years that renovation is more an art than a science. So many things have to be considered. Not just the methods, but the extent to which the plants will be trimmed back. Another key decision point is the health of the plants, the season, the environmental conditions, and plans for future crops.
I’m not going to go into all that right now. Suffice it to say that I recommend that one or a few plants are renovated at a time. You don’t want to take a chance with all your plants.
I’ll start this discussion with a reply to an email today from a customer who is having great success with their plants. They are growing in the garden in raised beds and in containers. They asked about cutting the plants back. Here’s the reply sent to them:
“Yes, the plants can be cut back to clean them up. Timing is critical and it is important to cut them back as little as possible. Once they have produced a crop they are messy because of spent bloom stalks and dead and dying leaves. The best and least risky way to clean them up is by hand by cutting out the bloom stalks and dead leaves. The next way would be to take a hedge clipper and trim them back, always leaving as much foliage as possible. The least desirable and not recommended way is to mow them down with a mower. Many will die as a result of this method.
The hardest thing to do after renovation is irrigation. The tendency is to overwater these plants to compensate for the trimming. Now that they have less foliage they will need less water, not more. Regularly overwatering leads to root rots. Some blame the trimming for the loss of the plants when in actuality it’s the irrigation.”
I’ll continue this discussion as time allows.
April 13, 2013 By Leave a Comment
We hope to expand on this subject in the near future. For now we’ll mention that we are using hornfaced mason bees and alfalfa leafcutter bees for pollination of our seed varieties. First chance I’ll add images. Being an entomologist this is a project that I love working with.
We released the mason bees from the refrigerator around April 1st, 2013. Today (April 13th) I saw the first bee entered a hole in the block. That was exciting. We hope that this is a sustainable undertaking. We purchased the initial bees during the winter. We hope that enough bees will be produced each year to help us grow our seed business.
It’s now May 2nd and I can report that the mason bees seem to be doing well. I have stood near the cages a couple of times to observe. I can see the bees moving from flower to flower. I haven’t seen them entering tubes in the domiciles. A bato bucket partially filled with clay soil and watered well has been placed in each cage as a source of mud for the bees. They have all they need, now it’s up to them. Here’s a pic of one of the pollination cages. This particular cage is being used to pollinate Fragaria vesca ‘Hawaii 4′. Plants are all in bato buckets and on a drip system..
April 13, 2013 By Leave a Comment
As of early April 2013 we have decided to move forward with a plug program. We are planning to commit to a screened facility so that we can ship plugs to all states. We can now take orders for 288 plugs for a number of varieties of Fragaria vesca and F. moschata. It is also possible to grow F. virginiana from seed, though we have not added any of these to the shopping cart.
Make sure and order early. Once we take the order we sow the tray(s). It takes 6 – 9 weeks from sowing to shipping. We think this is the most economical way to make these seed grown strawberries available. We are working on ways to make this size available to home gardeners.
October 1, 2012 By Leave a Comment
For some time now we have been shipping bare root plants to customers. Because of regulations and shipping costs this will be a more common method of delivering plants. Here are a few guidelines to follow when you receive your shipment:
- Unpack the shipment immediately
- Prior to planting in their permanent place, keep the plants in a shaded area and rehydrate
- Plant the plants asap. If you cannot plant within a day or two heel in or temporarily transplant into a container
- Make sure that the media is well drained and is slightly acidic
- Keep the media moist (but not wet) for at least the first two weeks after receiving the plants
- Mist to foliage several times daily if possible for the first week. Keep this to a minimum. Wet leaves for long periods of time create conditions for disease development/spread of disease
- Once planted, provide shade during the hottest periods of the day. If continuous shade is provided, gradually remove the shade over a period of a week so plants are not shocked. Direct sun on tender foliage can cause the foliage to burn.
- Do not over fertilize. High levels of fertilizer may cause root burn. Allow the plants to establish for about two weeks before starting high nutrient fertilization
August 10, 2012 By Leave a Comment
I just found out about the recently published Organic Strawberry Production Manual published by the University of California – Davis. I ordered a copy online at the URL below. Once I receive it I’ll likely have some comments to make. BTW: it costs $30 plus about $6 s/h. If you have the manual we’d love to hear your thoughts on its content.
The alpine strawberry crop this year was exceptional. The weather had a lot to do with this bumper crop. Another factor is our fine tuning irrigation and fertilization schedules. Check out these ‘Pineapple Crush’ berries harvested today, 6/22/12. I wish you could experience the aroma and taste of these exceptional berries.