Winter Tips

Adjust watering schedule for autumn, winter

WateringCan_NLEven though winter is here and plants are dormant they still need winter watering in our high desert climate.

We recommend thoroughly watering trees, shrubs, lawns and perennial beds at least once a month. Remember to water when temperatures are above 40 degrees, and with enough time for the water to fully soak into the soil.

Added water, along with a thick bed of mulch, will help protect plants throughout the harsh winter months.

Newly planted trees, shrubs and perennials are the most at risk. Try to water these 2-3 times a month. Fall-laid sod will also need extra moisture.

Finally, make sure that you disconnect and drain your hose after watering to avoid freezing pipes and to prolong the life of your garden hose. Please contact us with any questions. 

Winter watering for Houseplants

Plants need water – just not as much as you’d think.  Many people stick to a watering schedule of about once a week for their houseplants.  While this is generally a good rule to follow, you may need to change your habits in the winter.  The amount of water plants use is reflected by their environments:  they will use more in hot and bright locations, and less in dark or cool situations.  When winter comes, days are shorter so there’s less light and we generally keep our houses cooler, sometimes not by choice.

When winter comes, we should all be reducing the frequency of watering many plants.  They just won’t use it as fast as they do in the summer and this excess water will stay in the soil.  This can lead to a couple of problems with your plants: Root Rot and Fungus Gnats.  Root Rot is when the roots stay too wet for too long and start to rot away. And Fungus Gnats are insects that are usually more nuisance than actual problem.  Here’s a great source of info on Fungus Gnats: http://extension.colostate.edu/topic-areas/insects/fungus-gnats-as-houseplant-and-indoor-pests-5-584/

 We still recommend checking each plant by hand before watering to make sure they actually need it.  Break yourself out of your summer habits and cut back on most watering to avoid these problems. 

Are your evergreens looking yellow or brown? This might be why…

Extreme temperature changes over short periods of time during winter months can leave evergreen trees looking a little yellow and sad. There are a number of different reasons an evergreen tree might be turning yellow/brown and/or dropping needles this time of year. Sometimes it’s perfectly healthy, other times it’s not. How do you tell the difference, and what should you do? Here’s a few tips:

This pine is showing needle cast. Notice the brown needles are lower on the branch while the healthy green needles are closer to the tip.

This pine is showing needle cast. Notice the brown needles are lower on the branch while the healthy green needles are closer to the tip.

Needle Cast: If your conifer (pine, spruce, fir, or juniper) is dropping needles, it may be a perfectly normal and healthy occurrence. If the needles that are dropping are only on the interior part of the tree while the needles toward the ends of the branches are still flexible, green, and firmly attached, then your tree is going through a process called “needle cast.” This process is kind of like deciduous trees casting off their leaves every fall – the needles deepest inside the tree no longer receive much in the way of sunlight as they are shaded by the newer exterior needles, so the tree drops them. This is totally normal and you should not be alarmed.

Sun Scald: If the needles on one side of the tree are showing yellow or brown coloration, but the other side of the tree still looks healthy, it could be suffering from sun scald. The exceptionally dry winter air combined with low soil moisture and intense sun causes the needles to dry out. The damage is often only present on the most exposed parts of the tree where prevailing winds or southern sun can have the greatest impact. Often, only the tip of the needle will be discolored while the base of the needle remains green.

Some of this damage may be inevitable, depending on the location of the tree, but it can be mitigated by good winter watering (click here for more on winter watering). For particularly sensitive evergreens like boxwoods, arborvitae, and oriental spruce, to name a few, a permeable fabric like burlap can be used to wrap the plants, providing a little extra protection. Trees can also be treated with Wilt-Pruf, a product designed to give evergreen plants an added layer of protection on their needles and leaves. Generally, this type of damage is only short-term. Only in extreme cases do we start to worry about the overall health of the tree.

Freeze Damage: If your tree is dropping needles or yellowing/browning uniformly around the entire plant, there’s a chance the recent deep freeze caused such a shock to your tree that the needles were damaged.

Fort Collins Weather Nov. 2-15, 2014

Extended periods of warm weather followed by rapid temperature drops is the perfect formula for evergreen freeze damage.

Freeze damage on a Southwestern White Pine. Note the damage is present on the tips of branches while the interior needles remain green.

Freeze damage on a Southwestern White Pine. Note the damage is present on the tips of branches while the interior needles remain green.

When plants go through such a rapid change in temperature, they don’t have time to undergo the physiological changes that help them tolerate the cold. Cell walls can rupture when they freeze and the dry air can cause damage more easily than would otherwise be the case. In instances like this, the damage will be most prominent on the outer parts of the branches, causing the tips to discolor and lose needles while inner needles that weren’t as exposed during the freeze remain green.

Freeze damage on a Southwestern White Pine. Note the damage is not limited to just one side of the tree.

Freeze damage on a Southwestern White Pine. Note the damage is not limited to just one side of the tree.

In these cases, the only thing to do is wait and see. It is possible that in the spring, the buds that have already formed on the tips of those branches will still produce a new candle (the  growth from which new needles emerge). We encourage you to wait to prune until you are certain a branch has died, as cutting a branch that has a healthy bud on it will result in no growth next season. You can gently pinch the buds on damaged branches to find out if they’re still healthy – a firm bud is a healthy one, while a dried out dead bud will crumble between your finger tips. In this case, as with sun scald, the best treatment is a good deep watering 2 times a month through the winter when possible.

Come spring, even if no new growth emerges, if the remaining needles are still green, you’ve still got a healthy tree. Prune away the dead branches to expose the inner needles to light, give your tree a feeding with Jirdon Tree & Shrub fertilizer, and be sure to tell your tree how much it means to you and how happy you are that it’s still alive!

Winter care for woody shrubs, trees

Don’t forget to water your woody trees and shrubs! Pick a day through the winter that is over 40 degrees and water thoroughly through the winter.

Late winter is also a good time to prune deciduous trees and shrubs. Thinning cuts help encourage growth and increase the amount of light reaching inside branches.

Winter is also a great time to look at shape and structure of deciduous trees, find pest infestations and prune weakened branches (before Spring storms decide which branches should go for you!)

Winterize with rose collars

Hybrid Tea, Grandiflora, and other grafted roses need more winter protection than other varieties. Prune back long canes in November to protect them from snow damage, or wait until mid-April and leave the rose hips for winter interest. Remove debris from the base of the roses, and use a rose collar to hold soil, compost, straw or bark over the rose crown. We carry rose collars, which can be reused year after year. In the spring, the collars can also be used to protect starter tomatoes.

Start seeds now for strong, healthy plants

The winter months are an excellent time to get a head start on your garden! Seeds are a wonderful and cost-effective way to try new varieties of vegetables.

After choosing your seeds, be sure to follow specific starting instructions. Provide a draft-free 65-75 degree area, and a sunny window or full-spectrum grow light to get seedlings off to a great start. A special seed starting heating pad can help regulate temperatures and give your seedling the warm soil they love.

Fort Collins Nursery offers trays, plastic pots, peat pots, potting mix, and of course hundreds of varieties of organic, heirloom and traditional seed.

Questions? Ask one of our Garden Shop or Greenhouse representatives for ideas or recommendations to make this year’s garden something to talk about!

Dormant oil to knock out insects

If you have had an insect infestation, and are worried it will return to plague your fruit, shade and ornamental trees, dormant oil can be applied in late winter and early spring.

Dormant oils work to choke off insects where they over-winter inside trees. Some oils poison the pest insects, but leave many beneficial insects alone. Dormant oils, which are typically made from organic material, are safe to use on most plants, and around areas frequented by children or pets.

There are some oil-sensitive plants like junipers, cedar and maple the cannot tolerate dormant oil. Check with a Garden Shop representative if dormant oil is right for you.

Add amaryllis for indoor winter color

Amaryllis (Hippeastrum) are a great way to bring some magnificent color indoors during the gray winter months. Although they naturally bloom in the Spring, many are ‘forced’ to bloom around the holidays, making themamaryllis popular holiday plants with their large, showy, log-lasting blooms.  Their distinctive lily-like blossoms sit, often in clusters of up to four or five, atop the long thick stalks that emerge from the bulb.

These bulbs are easily grown indoors in a container. To grow an amaryllis in a container, plant the bulb in well-drained soil and leave the top one third of the bulb exposed. Place in a bright area with temperatures about 70F. Once foliage emerges, water regularly. Avoid over-watering to avoid root rot. When the bulb begins to bloom, you may find that the flower-heavy stalks need support. Use a slender bamboo stake and a plant-tie to keep the flower stalks upright.

After flowering has ceased, cut off the flower stalk. If the container has drainage, you can leave the bulb in this pot for years to come. If it does not have drainage, transplant it with fresh soil into a pot that allows drainage. Be sure to leave the top third of the bulb exposed. Large strap-like leave will push up out of the bulb. Keep the plant in a warm well-lit location, fertilizing every few weeks with a balanced fertilizer to help the bulb store nutrients for next year’s blooms. Water it often enough to keep the leaves from wilting or turning brown along the edges

In mid-August, stop feeding and cut watering back to significantly. In September, stop watering completely. Once the leaves have wilted and turned yellow, cut them off and move the bulb to a cool dark area, between 40-50 degrees, and forget about it for the next two months.

After two months have passed, water your Amaryllis once and wait for some green to appear. Once signs of life are apparent, move the bulb back into a warm light location and let the magic begin all over again!

Prune in early spring, late winter for a healthy tree

While light pruning can be done any time of year, early spring and late fall and are an excellent time for full-tree pruning. Prune before the tree has begun setting leaves so its resources are devoted to recovery.

Dead and diseased branches should be removed first, then secondary cuts for shape, structure (no lopsided trees!) and ventilation.

More on how to prune fruit trees or shade trees.

We also recommend professional arborists to do the work for you. Tall, old or diseased trees are not only an eyesore, but also a hazard for people and property.

We’d like to thank the folks at The Davey Tree Expert Company and Lumber Jack & Jill Tree Service for helping us clean up our long-established trees on the nursery. We will also be using the mulch they created to help over-winter the stock trees.

Cleaning beds, amending soils

Think there’s nothing to do in the winter garden? Think again! When garden soils soften, and days grow warm, amending soil and cleaning garden beds is the best preparation for a successful spring!

Rake leaves, grass clippings, and the remains of the vegetable garden from forgotten corners of the lawn and garden then add to your compost pile. If you use a pre-emergent for weeds, apply it now, but avoid areas that seeds will be planted directly into the soil.

Add amendments to garden soil and gently work it in (but avoid working the soil when it is very wet to avoid compacting your garden). We can help match our bagged amendments to your soil needs, but remember, nothing helps more than having your soil tested by Colorado State University’s Cooperative Extension office. Soil test kits are available at Fort Collins Nursery.