February Growing Tips
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By Raintree Horticulturist Theresa Knutsen
- Planting Tips for our Customers in the Deep South
- Soil testing/modifying soil pH
- Protecting early blooms from frost
- Blue Orchard Mason Bees
- Raintree Classes
- Dormant season spraying
- Container plant care
- Citrus Care
- Potted Bulb Care
- Overwintering potted plants
- Fruit Storage
- Tips for those of you doing your own grafting
- Frequently asked questions
Planting time has arrived for those in moderate winter climates including people living west of the Cascade Mountains in the Pacific Northwest. So long as the ground is not under water or water-logged, frozen or covered with snow, and the temperature is above freezing when you plant, you can plant dormant potted or bare root plants starting in February.
Planting at this time is almost as good as planting in the fall. Roots have plenty of time to dig in and establish before the tops of the plants start demanding water and nutrients. Colder areas of the country may have to wait until March, or later, to start planting. Be sure to read the Plant Owners Manual we send with your new plants for specific planting instructions.
Sometimes you might not be ready to plant when you receive your order. Or maybe weather conditions or your ground are temporarily not appropriate for planting. Hold your bare root plants, in the bag they came in, in a cool location that stays above freezing (35-40°F) up to two weeks, or heal them (bury) outside in a pile of loose soil or shavings in a shady location if you will need to hold them longer.
Add a little water to the bag if you do not see humidity collecting on the inside. It is important to keep the tops of the plants cool until planted, and the roots protected from drying out. See page 1 of the Raintree Plant Owners Manual for more details if you have to delay planting your new arrivals.
For our Customers in the Deep South!
We ship to California and Arizona in February but we can’t ship to the Southeast until early March because plants in transit could be damaged while crossing the frigid Rocky Mountains.
If you are in one of those southern sunny locations where the optimal planting time is before we are able to begin shipping to you, you may need to take special care with your plants when you do receive them. Please see our Plant Owner’s Manual, pg 2, for planting when the weather has warmed up instructions or the following:
- If you choose to plant out in a permanent location right away and your day time temperatures are in the mid-70’s or higher; mulch the soil surface well after planting, irrigate regularly to keep the soil evenly moist, not soppy wet, and provide shade until the plants are well-established. Warmer air temperatures encourage faster leaf and shoot growth than root growth, creating an imbalance between supply and demand in the plant. Shade helps to reduce the water needs of the plant and give the root system time to grow and catch up with the water demands of the top of the plant. As an alternative to providing shade you can whitewash dormant shrubs and trees. Make a 50/50 mix of interior white latex paint and water and spray or brush on. Apply from bottom to top if you use a brush, to avoid damaging the buds.
- Plant your new plants in a temporary, shady location, mulch, and water regularly through the summer. In the fall, when the worst of the summer heat has passed, move the plants to their permanent location. By the following spring they will be well-established and ready to perform.
- Plant your new plants in containers, or if you received potted plants put them in a somewhat larger container. Maintain them in a protected location, and plant in their permanent location in the fall when the worst of the summer heat has passed.
Dormant season pruning continues. See the Raintree Plant Owners Manual for basic pruning information, or check out our selection of pruning books.
Finish pruning grapes, kiwis, figs, maples, and other heavy sap producers this month, before the weather starts to warm, to avoid excess bleeding from the wounds.
Prune stone fruits (plum, cherry, peach, apricot, and almond) after buds begin to swell for the best healing response to your cuts.
Deciduous, summer flowering vines, such as Honeysuckle, Variegated Porcelainberry, or Tasmania Vine, will have dense stem networks after a few years. Thin out selected canes at their base to open the vines up and shorten remaining stems as needed to maintain desired size. Delay pruning of spring flowering vines until after they have bloomed, then apply the same approach to pruning as for the summer flowering vines.
Once the most damaging winter weather seems to be done, inspect shrubs, berries, and trees for dead and damaged wood and remove.
Prune indoor passion fruit and citrus, and other subtropical plants, just prior to, or as they are starting, their spring growth.
How well did your plants grow for you last year? A soil test might be needed if you noticed last years’ growth was weak, off-color (red summer leaves on blueberries, yellow leaves on bamboo, etc), or you are planting in a new soil area.
If you are using a soil test kit at home, use distilled water to mix with your soil sample, or you will be testing the water from your tap. A home soil test kit can give you an idea of the pH (acidity or alkalinity) of your soil, as well as the approximate amount of available nitrogen, phosphorous, and potassium.
You can also collect soil samples and send them off to a lab for a more professional test and supplement recommendations based on the crops you tell them you intend to grow. Ask at your local co-operative extension office for soil test lab recommendations, see Useful Links (in Growing Info) or search the internet.
For basic soil requirements of many of the plants we offer, such as pH requirement, drainage, and fertility refer to the Raintree Nursery catalog "How To Grow" boxes. On our website select Growing Info, then Plant Care, then the type of plant. It is important that the pH of the soil is within the preferred range for the plant you are growing. Plant roots can not do their job of absorbing nutrients properly if the pH is wrong, even if there are plenty of those nutrients in the soil.
Modifying Soil pH
You will need to add lime to your soil to raise the pH if the test shows the pH of your soil is lower than the range the plant you are growing prefers. One pound of agricultural lime mixed into 10 square feet of soil surface will raise the soil pH one point.
If your soil pH tests higher than what is recommended for the plant you are growing, you will need to add ground sulfur to lower the pH. The amount of sulfur to add varies with the soil structure, and needs to be mixed into the soil. For example: To affect a 100’ square area, mixed to a depth of 6 inches, starting at a ph of 7.00 and changing to 5.5: add 1.5 pounds sulfur to a sandy soil, 3 pounds to a silty/loam soil, and 6 pounds to a clay soil.
A professional soil test and recommendations will be able to be more specific, or your local co-operative extension service should have application recommendation charts or bulletins. Microbes in the soil will convert elemental sulfur to a form plants can use, when the soil is warm enough for them to be active. Don’t expect much change in the pH to occur until the soil has been warm for a while.
If you want to do a follow-up test, to see if your application was effective, wait at least 6-9 months to give the amendments some time to break down and affect the soil pH. It would be even more effective to check your soil about the same time each year, and make adjustments just one time per year.
A surface application of finished compost (½-1” thick) or earthworm castings (1/4-1/2” thick) is often enough nutrient supplementation for the back yard grower. Spread the amendment under and just beyond the edge of the leaf canopy of established berries and fruit trees, where the active nutrient seeking part of the root system is. If your plants are growing in a lawn, drill holes 6-8” deep every 1-3 feet along the drip line and fill with the amendment to keep the nutrients away from the grass roots. Raspberries and rhubarb respond well to the addition of cow or steer manure, applied in winter. Acid loving plants, such as blueberries, appreciate a top dressing of wood chips or other material that is acidic as it breaks down.
Hard frosts following winter warm periods can damage early blossoms. If you are growing early blooming fruit varieties in areas with warm winter periods and late frosts, some years you will not have much or any fruit on those trees.
Temperatures below freezing do not necessarily kill blossoms. For instance, some Asian Plums have still fruited with temperatures several degrees below freezing during the bloom.
There are things you can do however to protect the blossoms from frost. You can protect blossoms on early blooming trees such as apricots, japanese plums, peaches and nectarines from frost with burlap or Reemay type woven fabrics draped over the tree when there is danger of hard frost.
Some growers use mist; leave misters on over night when frost threatens. As the mist freezes on the blossoms a small amount of heat is released. You could experiment with outdoor Christmas lights. Arrange the bulbs throughout the tree canopy, and turn them on when frost threatens. The small amount of heat given off by the bulbs may be enough to prevent damage. LED bulbs give very little heat, so try to find some older type bulbs.
If frost protection at night is necessary, then bees may also not be active during the day. If you are not seeing any bees you might want to hand pollinate some of the blossoms yourself.
Now is the time for Blue Orchard Mason Bees
We will continue to ship mason bees through the end of February or until supplies run out. When you receive your bees they need to be kept cool until you are ready to release them. Keep them in the refrigerator at 36-39°F. It is important to maintain proper humidity for the bees in a frost free refrigerator. Poke several small holes in a plastic bag, put the cardboard box of cocoons inside that bag along with a barely moist paper towel, close the bag, and put it in the refrigerator.
Mason bees will emerge naturally, in response to warming spring temperatures, if you set up the nest box and release box (with cocoons inside) as soon as you receive them.
They will survive short periods of exposure to temperatures below zero, but if you will be experiencing long periods of sub-freezing weather it will be best to store the bees in the refrigerator. Storing your bees in the refrigerator allows you to time the release of your bees to coincide with the bloom time of trees, or groups of trees, in your orchard.
If you are just starting a population, you will need to release all of your bees at the same time. In the future, as your population of mason bees increases, you can manage them and release a portion as each group of trees comes into bloom. Release the bees as you see flower buds in your orchard swelling, or about 3 weeks before you expect the flowers to open. Or put a quantity of cocoons out every six weeks.
To release your mason bees, place the straws containing the cocoons in the cardboard release box they arrived in, #T343C 6" release box, or a Starter Cottage (T333). Locate the release box just under or otherwise near your bee block, so the females will find their new clean block when they return from their maiden flight.
Some of the bee condos we sell have room inside for the straws, or you can make a release box from a tin can or cardboard box. Margriet Dogterom’s book “Pollination with Mason Bees” (#S427) has instructions on making release boxes.
The bees like to emerge from a small dark hole into the rising sun to the east, stepping out onto a small platform they can get their bearings from before taking flight. The hole needs to be above the bottom of the release box, and the same diameter as the straws or tubes in your nest box.
Locate the release box near the nest box the bees will use, so they know where to find it. Be sure to have new, clean places for your bees to deposit their eggs into when they emerge, although it will be a few days before they are ready to use them. Either insert new clean straws in the Calm Bee Nation blocks you used last year, or set out Bee Diverse Stacked Trays you cleaned last fall after removing and storing the bees.
Adult mason bees need nectar to forage on as they go about their work of collecting pollen -- especially those that emerge early -- before there are many blossoms on your fruit trees. Plant early nectar forage sources, such as pussy willow or filbert, to help maintain a healthy mason bee population. Pieris japonica, Indian Plum (a northwest native), and Oregon grape are also good sources of nectar. Bumble bee, honey bee, and other early foragers will appreciate those early blossoms as well.
Raintree also offers Green Berry Bees (Osmia aglaia), a relative of the Mason Bee. They pollinate late spring and summer blooming berries, kiwi, and garden vegetables. Green Berry bees wake up as the Mason Bees come to the end of their cycle, and continue flying into the summer. This beautiful little hard-working shiny green bee is native to the Pacific Coast and suited for and only available to ship to OR, WA, and CA.
Learn about pruning, plant selection, grafting, landscape design, and other topics, attend classes at Raintree Nursery this year. Find out when and where by visiting our Raintree Workshops page.
We also participate in other classes in the Puget Sound Region in association with the Seattle Tree Fruit Society, and the Western Washington Fruit Research Foundation.
If you check with your local co-operative extension office or fruit enthusiast garden club you may find a class you can attend in your area.
Dormant Season Spraying
Late winter is the time to apply dormant oil spray to control insects or eggs over-wintering on the trunks or limbs of your trees. Focus on trees you saw significant infestations of aphid or scale in last year. Some dormant oil products may have insecticide in them to enhance their effectiveness, or fungicide to allow you to accomplish more with a single spray. I prefer to know what insect or disease I am treating, and use the best product and spray schedule for it in my area. Sometimes overlaps in timing may occur, in which case a combination product could be used.
Fungal diseases can be prevented with fungicides, but often not eradicated, once infections occur. Sanitation is important, cleaning up leaves and debris that may harbor fungal spores helps reduce the amount of innoculum present. Start applying Fireblight controls in early spring, fixed copper sprays or Bordeaux mix are effective. Fixed copper sprays are also effective against pseudomonas or bacterial canker, applied in early spring and late fall; and Corynium blight (shothole disease) in stone fruits applied early fall, winter, and spring. Brown rot can be controlled with copper, sulfur, or lime sulfur sprays, applied at petal fall, mid-summer, and fall. Apply your third spray to control peach leaf curl, about 4 weeks after your second spray in late January.
Scab in apple or pear trees can be managed with lime sulfur, sulfur, fixed copper, or Bordeaux spray, applied when conditions are right for infection to occur. Apply the spray immediately following an extended wetting period in which the fungal spores are able to germinate. At cooler temperatures (below 48°F) the wetting period is 12-24 hours, or longer. Above 48°F, the wetting period will be less than 12 hours. Or spray by the calendar, starting just prior to the flower bud scales starting to open, and every two to four weeks, depending on the amount of rainfall and the temperature you are experiencing. Do not apply spray when the blossoms are open and bees are visiting the flowers. The most critical time for scab control is from the breaking of the flower buds until leaves are fully expanded.
Refer to the 2015 revised Raintree Nursery Owners Manual for a quick guide of when to treat for fungal diseases. Contact your local co-operative extension service to find out what the typical disease and insect problems are in your location, and the best recommended products and treatment times. Always follow label directions for mixing insecticides and fungicides.
Container Plant Care
Enjoy fragrant blooms as citrus begin to flower. Start feeding, at half the normal dose, as plants start to put on new growth. Your diligence last fall checking for and treating insects on citrus plants and other indoor plants should reward you now with insect free plants, but it’s still a good idea to continue to monitor.
Prune indoor passion fruit and citrus, and other subtropical plants, just prior to, or as they are starting, their spring growth.
Potted Bulb Care
Dig up potted bulbs you sunk in the ground last fall to force for early spring color. Keep them in a cool greenhouse or basement and provide 12 hours/day supplemental light. When flower buds start showing some color bring them inside to enjoy. The flowers will last longer if they are kept cool overnight.
Overwintering potted plants
Regularly check your potted plants that are over-wintering in a cool protected location. Make sure the soil remains moist, but not sopping wet, so roots don’t dry out. If the potential for hard freeze, (temp below 25° F over night) or daytimes staying below freezing is past it is time to bring your dormant plants back outside. If a surprise late freeze occurs you should bring them back in, temporarily, to avoid freeze damage. So long as the plants remain dormant you can also continue to keep them at 35° -40° F. if you don’t trust the weather reports.
Check stored fruit for rot, discard or use any fruits with bad spots. Many fruits will still be in excellent shape. Red Belle de Boskoop, Karmijn de Sonneville, Enterprise, King Edward VII and Melrose apples all have a long storage life. Comice, Bosc, Highland and Conference European pears, and Korean Giant and Chojuro Asian pears also store well, though not quite as long as the apples. Medlar and Kiwi have a long storage life when picked at the firm ripe stage (seeds mature but fruit still firm) and kept cool. Bring them into a warm place for several days to finish the ripening process.
Tips for Those of You Doing Your Own Grafting
Plant rootstocks for budding. Stone fruits, such as apricots, peaches, cherries, and nectarines, and certain cultivars of other fruits propagate most reliably from summer budding, though all but peaches and nectarines can be grafted in early spring. Budding is also an excellent technique for making the largest number of trees from a limited quantity of scion wood. I will explain the technique more in the August Growing Tips, but it is important to have an established rootstock to graft the bud to. Now is the time to acquire and plant the rootstocks you want to bud on to next summer. Plant them in a garden row, about 12” apart in the row. You may also plant them in a container. Keep them watered and growing at a steady pace throughout the summer so they are still growing in late August when it is time to bud graft. If you are planning to make your own combo trees you may choose to wait one more year before you bud, so you can graft the branches on at a taller point on the tree.
In some areas of the U.S. spring budding is more successful than summer. If your springs tend to be moderate and your summers hot spring budding may be your best choice. Your local co-operative extension office, or local garden club, may be able to help you determine which is the best time for your area.
Bench grafting is done during the dormant season. Dormant scion wood is grafted to a bare root rootstock that is either dormant or starting to grow, and held at 60-70 °F for 10-14 days to give the wounds time to start healing. The new plants are then held at cooler temperatures (35-45 °F) until the risk of hard freeze (which can damage the new cells in the graft union) is past and it is safe to plant them outside. It is best to plant the newly grafted trees in a garden row, or keep them in containers, rather than in their anticipated permanent location. The new graft unions are fragile and could easily be damaged by children, pets, or string trimmers. After a season of growth your new trees will be stronger and taller, less likely to be damaged.
We will ship rootstocks to you when we ship the rest of your order, and rootstocks often are not available until February. Keep your harvested scion wood in the refrigerator, if prepared properly it can hold several months. See the December Growing Tips, or the rootstock section, pg 60 in the catalog, for scion harvesting and storage tips. If you are not able to do your grafts right after you receive your rootstock that is OK. It is more important that the scion wood be dormant than the rootstock. Just keep the roots moist so the rootstock does not dry out.
There are several techniques used for bench grafting, the booklet ‘Budding and Grafting’ (#S050) explains the most common techniques.
There are a few tools you will need to make your grafts. If you choose to use a knife it needs to be very sharp, and have a single beveled edge (most kitchen and pocket knives, in comparison, have two beveled edges). You might prefer to use a grafting tool instead, that makes an identical cut in both the rootstock and the scion wood for you with a squeeze of your hand. Then you will need something to hold the grafted pieces together securely and hold moisture in – we offer grafting bands for that purpose (#T240).
Some people use black electrical tape, but be aware that its lack of flexibility can girdle your new graft before you cut it loose, and if you do cut it loose early enough, its stickiness can damage the new callous tissue or the bark as you pull it away.
Finally, you will need a good pair of pruners to trim the scion piece after you graft, and a sealant to hold moisture in where you trim the scion piece. See our Grafting Supplies page for specific suggestions, including the Scionon Grafting Shears (#T250) we are offering this year. The new design of this grafting tool does a superior job making the grafting or budding cuts, and can be used for both bench and field grafting or budding.