Strawberries and raspberries under mulch and hail
June-bearing versus day-neutral strawberries, floricane versus primocane raspberries, and why blueberries are not the substitute.
Strawberries and raspberries can be the most productive square footage in a high-country garden, or a three-year disappointment, depending on which kind you planted and whether you mulched them at the right moment. The kinds are not interchangeable.
A June-bearing strawberry and a day-neutral strawberry want different bed management. A raspberry that fruits on second-year canes and a raspberry that fruits on the current year’s canes fail differently when a May frost hits. Pick the system before you pick the cultivar name.
Strawberries: one heavy crop, or a long trickle
June-bearing cultivars set a single heavy crop in early summer on plants that formed their flower buds the previous fall. They are the ones for jam, when you want a lot of fruit at once. They also send many runners.
You renovate the bed after harvest by narrowing the rows and removing old leaves, and you let a controlled number of runners fill the gaps. In a short mountain season the “June” crop may be July. The name is the type, not a promise about the month.
Day-neutral cultivars flower and fruit across the season as long as temperatures stay in a range they tolerate. They are the better choice for a small bed where you want a bowl every few days, and they produce fewer runners, so you set them and let them clump.
They slow or stop when summer heat spikes, which on the Front Range means a pause in the hottest weeks and a return as nights cool. In a mountain summer that never gets that hot, a day-neutral can fruit more steadily, which is one of the quiet advantages of a cool site.
Plant in spring as soon as the soil can be worked, crowns at the soil surface.
A buried crown rots. A crown sitting high dries out. Space them so they are not a solid mat in year one.
Water steadily while they establish. Strawberries are shallow. A missed week in a windy June is a small berry or a dead plant.
The winter mulch, timed to the freeze
This is the step that gets skipped. After the soil has begun to freeze, cover the plants with straw a few inches deep. The mulch keeps the freeze steady and protects the crowns from drying wind and from heaving.
Put it on earlier, while the soil is still warm, and you insulate an active plant and invite rot and voles. The timing principle is the same one on the mulch page.
Pull the straw back in spring when growth starts, and leave some of it in the paths to keep the fruit off the mud. In a town with unreliable snow and a hard January wind, this mulch is not optional. It is the crop.
Hail and birds take ripe fruit. A low hail cloth frame over a strawberry bed pays for itself the first time a June storm crosses the Palmer Divide. Net if robins are already working the yard. Pick every other day in the flush so fruit does not mold.
Raspberries: which cane carries the fruit
Floricane raspberries fruit on canes that grew last year. A late spring frost that kills the blossoms, or a winter that kills the canes to the ground, removes the crop. Summer-bearing cultivars in this class can be excellent on the Front Range when the canes survive. They are a gamble where chinooks deharden wood and a May freeze is routine.
Primocane raspberries fruit on the current year’s canes, often in late summer and fall, and many of them will also fruit earlier if you leave the canes for a second year.
The practical mountain and high-plains system is to mow or cut all the canes down in late winter and take only the late crop on new growth. You sacrifice the early flush and you escape the winter-killed floricane problem entirely. Where the first fall frost comes in early September, a late primocane crop can still get cut short.
Choose an earlier primocane cultivar and put the row in the warmest bed. On the Front Range, with a longer September, this system is one of the most dependable fruits you can grow. Heritage and Caroline are widely grown examples of the primocane class, not a trial ranking from this site.
Plant raspberries in a row you can reach from both sides, with a simple wire so the canes do not flop into the path.
They spread. A bed with a mowed border or a buried edging you actually maintain will contain them. A bed against the ornamental border will become the ornamental border.
Full sun, decent drainage, mulch on the soil and not buried against the new shoots. Water while the fruit is sizing. Then ease off so the canes harden for winter if you are keeping them.
Yellow leaves are often the soil
CSU’s iron chlorosis list includes raspberry. On wet, alkaline clay the new leaves yellow between the veins, the same symptom as on a silver maple. The fix is not a blueberry acid program.
Improve drainage, stop overwatering, add organic matter, and if the bed is truly hostile, grow currants, which are the more forgiving shrub. That comparison is on the currant page. A foliar iron spray is a temporary cosmetic, with the limits in the soil article.
Do not plant blueberries in the ground as the substitute. They want a pH these soils do not have.
A bed plan
Give strawberries their own bed. They do not thrive in the shade of a raspberry cane, and the renovation schedule is different. Day-neutrals in a four-by-eight raised bed, mulched with straw after freeze-up, will feed a household its fresh fruit.
June-bearers need more room if you want enough for jam. Raspberries in a separate row fifteen or twenty feet long, primocane type if your winters or your springs kill canes, floricane only if you have seen canes survive in your own yard.
Both crops attract voles if the mulch is deep and the fruit is on the ground. Keep straw off the crowns until winter, then use it, and pull it back.
A hardware-cloth bottom on a strawberry bed is worth it if voles are already in the yard. Rabbits will take canes in winter.
A short mesh fence is enough for rabbits and useless for deer. Deer eat raspberry leaves and strawberry plants. If deer are regulars, the fruit garden goes inside the same tall fence as the vegetables.
Checklist
- Choose June-bearing for one heavy crop and runners, day-neutral for a long trickle.
- Set strawberry crowns level with the soil.
- Mulch strawberries after the ground starts to freeze, and uncover them as they grow in spring.
- Choose primocane raspberries and cut them down each winter if spring frost or winter kill takes floricanes.
- Give raspberries their own row. They spread.
- Treat yellow new leaves as a chlorosis and drainage problem.
- Do not plant in-ground blueberries as the replacement.
- Cover the beds for hail if you garden in hail alley, and net them for birds.
Sources
- CSU Extension, Iron Chlorosis of Woody Plants.
- CSU Extension, Colorado Vegetable Guide, on wind, hail, and the value of covers.
- University of Idaho Extension, BUL 859, on matching fruit types to short, harsh seasons.
- CSU CO-Horts and the Colorado Climate Center hail window, for why a cloth over a berry bed is a normal structure rather than an overreaction.